Webinars 347

The Dark Energy Survey https://www.darkenergysurvey.org/, a major international effort to map the southern sky for cosmology, is actively producing scientific results in many areas of astrophysics. The DES data products are distinguished from other surveys by the combination of area of sky, depth, and photometric precision. The principal cosmological probes include measures of geometry from supernovae, the baryon acoustic oscillation feature, and counts of galaxy clusters, as well as measures of the growth of structure over cosmic time from galaxy correlations and from weak-lensing shear correlations. The Year 3 joint analysis has placed the tightest constraints on cosmological parameters for a survey of its kind and the complete Year 6 will follow. In addition, DES data are powerful for exploring structure within the halo of the Milky Way, such as discovering and characterizing ultra-faint dwarf galaxies and stellar streams. The time domain can be explored as well, especially within the special deep fields that were designed for discovery of supernovae. This talk will review the current status of the project and will outline some recent scientific results.

The Vera C. Rubin Observatory is under construction in Chile. When completed, in 2024, it will be used to carry out the Legacy Survey of Space and Time (LSST), in which the entire night sky will be observed every few nights, for ten years. The LSST data set will revolutionize every field of astronomy because of both the scale and uniformity of the measurements. As an example, LSST will observe more than 5 million asteroids, allowing us a rich and detailed probe of the evolution of our Solar System. The LSST data stream will be so large that traditional methods of handling the data will not be successful - new, computationally efficient approaches are required. Our team is developing the Solar System Notification Alert Processing System (SNAPS), which is designed to ingest measurements of asteroids and derive their physical properties. We identify outliers - asteroids whose properties are unusual - both in real-time and in daytime processing. We are building a public interface to our database and results. In this talk I will present the overall structure and performance of SNAPS, provide some interesting examples, and talk about the science that we are presently doing, using the data stream from the Zwicky Transient Facility as a testbed.

TroyRaen_LIneAwebinar_20211202.pdf

The Pitt-Google collaboration is developing a 100% Google Cloud-based alert broker for Rubin Observatory’s upcoming LSST. In this talk, I will discuss our pipeline model and the compute & data storage/delivery solutions we employ. These are significantly different from those of other brokers, and I will discuss the benefits and tradeoffs. Our pipeline uses an event-driven microservices model. It is highly modular and requires almost no infrastructure management. It runs predominantly on services like Cloud Functions and Cloud Run, which are triggered by individual alerts/messages and scale automatically. For data storage and delivery, we use BigQuery, Pub/Sub, and Cloud Storage. BigQuery is a data warehouse optimized for big-data analytics, and is accessible via standard SQL and (optionally) TAP/ADQL. Pub/Sub is a streaming message service, similar in function to Apache Kafka but requiring no data management. Each module in our pipeline publishes a stream. All of our data resources are public. Users can compute next to the data and take advantage of Google Cloud services, or take the data out of the Cloud via Google’s APIs. I will discuss these topics with an eye toward LIneA’s work on becoming an IDAC for LSST.

ALeRCE broker - LINEA.pdf

FontRibera_LineA.pdf

From 2009 to 2019, the Baryon Oscillation Spectroscopic Survey (BOSS) and its extension eBOSS used the SDSS telescope to obtain precise redshifts for millions of galaxies and quasars. From the distribution of these objects, we were able to get very accurate measurements of the Baryon Acoustic Oscillations (BAO) scale from redshift 0.2 to redshift 1.5. At the same time, BOSS and eBOSS obtained optical spectra of over 210 000 high redshift quasars (z>2.15) with the goal of detecting the BAO feature in the clustering of the intergalactic medium, using a phenomenon known as the Lyman alpha forest (LyaF). In this talk, I will overview the final results from the LyaF dataset of eBOSS, including a 1.5% measurement of the BAO scale at z=2.33 presented in du Mas des Bourboux et al. (2020). I will also give an update on the status of the Dark Energy Spectroscopic Instrument (DESI). In the next few years, DESI will increase the current spectroscopic dataset by an order of magnitude. It will provide an exquisite measurement of the expansion over cosmic time, while at the same time addressing other interesting questions: the sum of the mass of the neutrino species, properties of dark matter particles, tests of general relativity and the shape of the primordial power spectrum of density fluctuations.

talk_Hernitschek.pdf

Nowadays large-scale astronomical surveys enable us to see the universe in a much more detailed, and in particular different way than before. In the era of such large-scale surveys, methods to handle investigate these data, and especially to classify sources, become more and more important. The LSST survey, carried out by the Rubin Observatory, will distribute its data in a new way: LSST will produce a nightly so-called stream of public alerts that will disseminate new information about transient, variable, and moving objects within 60 seconds of readout. Software systems called \'community brokers\' will process the LSST alert stream, add scientific value by such as cross-matching with archival catalogs and machine-learning based identification of objects, thus providing science users with the ability to identify targets of interest and trigger follow-up observations in a timely manner. In this webinar I will give an overview of LSST community brokers in general, and specifically describe the \'Point of Interest\' broker developed by a small team at Vanderbilt University.

I will outline the recent developments in mapping out the expansion rate of the universe and the growth of density fluctuations in order to better understand dark energy and, eventually, identify the physics responsible for universe\\\'s accelerated expansion. Then I will present a holistic overview of the recent Year-3 results from Dark Energy Survey, currently the largest experiment mapping the large-scale structure in order to probe dark matter and dark energy.

In this decade, Vera C. Rubin Observatory will obtain high-resolution optical images of the Southern Sky at unprecedented depths. Rubin public alert stream will communicate the detection of millions of potential transient objects every night. The key to use this stream is to be able to select promising transients and to automatically connect them to teams and observing facilities. I will introduce Fink, a broker developed on high-end technology and designed for fast and efficient analysis of big data streams. It has being chosen to process the full Rubin optical time-domain data stream. Fink enables the selection of promising transients by providing preliminary classifications based on machine learning algorithms and combining information from catalogues and surveys. Within minutes, Fink is able to communicate these candidates to teams and follow-up facilities. We are already deployed using ZTF data and have ongoing collaborations in a wide range of science including supernovae and multi-wavelength/messenger events as kilonovae and Gamma Ray Burst afterglows.

ANTARES is a time-domain event broker developed and operated by the NSF\\\'s National Optical-Infrared Astronomy Research Laboratory. It provides a platform for community-driven processing of alerts. After ingesting alerts, the ANTARES system cross matches them with extant astronomical catalogs and annotates them with additional contextual information, including any past history of alerts at that location. The ANTARES processing pipeline then applies filters, which can be user-supplied, to sort and classify alerts based on features, both from the alert itself and the contextual information. These sorted subsets are then distributed to interested astronomers. I will provide an overview of the system including its performance in processing the public Zwicky Transient Facility alert stream, our scaling tests that will ensure we are ready for the Vera Rubin Observatory\\\'s Legacy Survey of Space and Time, and demonstrate how anyone can write a filter and begin getting personalized alerts now.

Galaxy_surveys.pdf

In the first part of this talk I will review the state-of-the-art techniques used for the analysis of the results of the BOSS and eBOSS galaxy survey maps. In the standard approach galaxy clustering measurements from spectroscopic surveys are compressed into baryon acoustic oscillations (BAO) and redshift space distortions (RSD) measurements, which in turn can be compared to cosmological models. I will present the main cosmological results of BOSS-eBOSS which represent the state-of-the art cosmological measurements from galaxy spectroscopic surveys. In the second part of the talk I will introduce the on-going redshift survey DESI, and will present some novel techniques that will be used in this up-coming dataset to make the cosmological analysis blind and to extract further extra information beyond BAO and RSD signals.

The current tension on the measured value of the expansion rate of the Universe today (H0) has pushed the cosmological community to pursue more measurement techniques and larger datasets. One such technique, the characterization of systems with gravitationally lensed supernovae, is of particular interest in the Rubin Observatory era for two reasons: (1) thousands of these systems will be detectable by the Rubin Observatory when only a handful exist in current datasets, and (2) each identified system offers an independent measurement of H0, enabling high precision over the 10-year Legacy Survey of Space and Time. In this talk, I present a novel deep learning architecture for lensed supernovae detection that identifies more lensed supernovae (90 percent of the expected population) than any other previously proposed method.

Brazil Seminar - image processing.pdf

In this talk, I would explain from basic principles the theory of detecting point sources in ensembles of astronomical images (Zackay & Ofek 2017 a, b) and the theory of \\\'proper image subtraction\\\' (also known as ZOGY) (Zackay, Ofek & Gal-Yam 2017). Then, time permitting, I would explain future efforts to extend these operations to undersampled images in preparation for the ULTRASAT space mission, led by the Weizmann institute of science.

Seminar_linea.pdf

Covariance matrices are among the most difficult pieces of end-to-end cosmological analyses. Advancements in cosmological surveys lead to larger data vectors and, consequently, increasingly complex covariance matrices, whose number of elements grows as the square of the size of the data vector. The most certain and forward way of comparing these matrices is in terms of their ability to reproduce cosmology, that is, by performing a full Bayesian analysis. This approach, however, can be very time consuming and computationally demanding. Using the concept and construction of compression schemes, which have become increasingly popular, we propose a fast and reliable way of comparing covariance matrices via a fast Monte Carlo simulation. In this talk, I will give an overview of cosmic shear, before moving on to the topic of covariance matrices. I will then motivate the use of compression schemes and show that they can be powerful tools for comparing covariance matrices. I will conclude by showing some of the exciting results obtained with our python algorithm.

ClaudiaBauzerMedeiros-LINEA.pdf

A Ciência Aberta é um movimento mundial cujo principal objetivo é permitir que pesquisadores em qualquer lugar do mundo possam colaborar por meio do compartilhamento dos seus resultados de pesquisa - como por exemplo dados, software, modelos ou publicações. Os principais valores associados são inclusão, transparência, e pesquisa confiável e reprodutível. A astronomia é uma das áreas em que este movimento se destaca, pela ampla publicação de catálogos, pelo compartilhamento de dispositivos e software, e pelas publicações envolvendo uma grande quantidade de pesquisadores do mundo inteiro. O que falta fazer? Como outras áreas do conhecimento vêm tratando do assunto? Práticas de Ciência Aberta estão se tornando obrigatórias em um grande número de países e, inclusive, exigidas para submissão de projetos a agências de fomento de todo mundo. A palestra vai apresentar o movimento de Ciência Aberto a partir das diretrizes de 2021 da Unesco, e dar exemplos de como estão sendo seguidas, incluindo obstáculos para sua realização plena.

Charged_black_hole_in_entangled_relativity - Prese

The main goal of this seminar is to present a black hole solution in a new theory of gravity, which we call Entangled Gravity. In this theory, spacetime itself cannot exist without the presence of matter. To motivate the study of new theories of gravity, I will start by giving a broad review of Einstein\\\\\\\'s general relativity (GR) and recall some of its successes and failures. As we impose modifications to GR, Entangled Gravity will naturally appear as an adequate alternative to explain the Universe. In the context of this new theory, a black hole solution will be proposed which is indistinguishable from the usual Schwarzschild black hole solution from GR.

DESY3_hcamacho_12082021.pdf

The Dark Energy Survey (DES) has recently released cosmological analyses from its first three years (DESY3) of observations, imaging 5000 square degrees in the southern sky. We review the novel advances in the methodology required to extract and combine galaxy clustering and weak lensing information in the DESY3 data. We present some of the main results, focusing on the combination of three two-point correlation functions, the so-called 3×2pt, and the BAO feature detection analyses, and discuss its cosmological implications.

Chariklo_LINEA.pdf

The Centaur (10199) Chariklo is a small body moving in an elliptical orbit between Saturn and Uranus. In 2013, Braga-Ribas et al. (2014) discovered two rings orbiting this Centaur using stellar occultation, and this was the first time that rings were observed around a small body. In this talk, I will present the obtained results from stellar occultations by Chariklo observed between 2013 and 2020. I will present the global shape of Chariklo\\\\\\\\\\\\\\\'s rings system and the 3D shape of Chariklo\\\\\\\\\\\\\\\'s main body. The parameters obtained in this work should be useful for constraining dynamical models of Chariklo and its rings and provide new insights into the formation and evolution of this system.

Linea_22jul21.pdf

The standard model of Cosmology (SCM) consists on the LCDM model, which is dominated by cold dark matter and Cosmological Constant. Although this model provides the best description of cosmological observation thus far, the nature of these two components remain unveiled. Therefore, there is an urge to develop models to explain them, but on top of that, we need to put the fundamental hypotheses underlying the SCM under scrutiny. After all, statistically significant evidence of departure of these hypotheses may lead to complete reformulation of the SCM. In this talk, I present some observational tests I carried out with this goal. I will talk about some observational tests of the Cosmological Principle - namely, the assumption of large-scale homogeneity and isotropy of the Universe - using a variety of cosmological data. In addition, I will show results obtained by probing the validity of two fundamental assumptions which these data relies upon: the constancy of the absolute magnitude of Type Ia Supernovae, and the current temperature of the CMB.

LIneA_15jul2021.pdf

The proximity of near-Earth asteroids (NEAs) allows us to investigate the physical properties of small bodies down to the decameter-scale. A dedicated space mission to such small NEAs will be key to shed light on accretion mechanisms that took place in the protoplanetary disk. Extended ground-based observations will be also fundamental to fully characterize the physical diversity of the NEA population, whose discovery rate is exponentially growing in recent years. Besides its relevance for our understanding of the solar system and planetary science, NEA investigation is also essential to assess the potential exploitation of the asteroidal mineral resources in the near future, as well as to increase our capacity of mitigating the asteroid threat of collision with the Earth. I will present and discuss some recent results and future perspectives related to the science of NEAs, with a particular focus on small-sized objects.

Bringing Reliability to your Data Lake with Apache

Apache Spark has become the de-facto open-source standard for big data processing for its ease of use and performance. The open-source Delta Lake project improves Spark’s data reliability, with new capabilities like ACID transactions, Schema Enforcement, and Time Travel. This helps to ensure that data lakes and data pipelines can deliver high-quality and reliable data to downstream data teams for successful data analytics and machine learning projects. Join us to learn how Apache Spark 3.0 and Delta Lake enhance Data Lake reliability.

PALESTRA_LINEA_01JUL2021_WBCORRADI_FINAL.pdf

O Laboratório Nacional de Astrofísica (LNA) é a Unidade de Pesquisa do Ministério de Ciência, Tecnologia e Inovação (MCTI) responsável por planejar, desenvolver, promover, operar e coordenar os meios e a infraestrutura para fomentar, de forma cooperada, a Astronomia Observacional Brasileira. O LNA possui a importante tarefa de gerenciar o Observatório do Pico dos Dias (OPD) e a participação brasileira nos observatórios internacionais Gemini (Norte, no Havaí e Sul, no Chile) e SOAR, no Chile, além de outras iniciativas como o PanEOS, LSST e LLAMA, por exemplo. Além disso, participa ativamente na concepção e construção de novos instrumentos astronômicos e sistemas periféricos. Pretendemos apresentar os avanços na instrumentação e o impacto da ciência realizada com os telescópios gerenciados pelo LNA, a partir de uma perspectiva histórica, nesses 35 anos de sua existência.

lineA_webinar_machine_learning.pdf

Machine Learning and Deep Learning have revolutionized many domains, and have sparked a burst of interest in astronomy as well. Astronomical datasets, being large, rich, and consisting of the beautifully complex ingredients of our Universe, seem to offer the perfect testbed for such tools. Past, ongoing, and future surveys have provided or are expected to provide multi-color and multi-temporal observations of hundreds of millions of stars and galaxies in our Universe. The application of Machine Learning tools to these datasets may offer new and exciting opportunities, but it also raises several questions. Will Machine Learning revolutionize the field of astronomy as well? Will it have a dramatic impact on our data processing pipelines, on the models we deduce from the data, or on the types of scientific questions that we ask? In this talk I will review different types of Machine Learning algorithms and will present some example applications of these tools to astronomical datasets. I will describe the current state of the field, focusing on the challenges we face. I will finish by proposing an approach that might help us harness the full potential of these tools in the future.

20210610-RobertNikutta-Datalab-Linea-static.pdf

The Astro Data Lab (https://datalab.noirlab.edu), or Data Lab for short, is an astronomical science platform developed at NOIRLab. It is open and free to all who are interested in astronomy, data science, and education efforts. Launched 4 years ago to enable remote access and analysis of survey data products generated by NOAO\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'s telescopes, such as the Dark Energy Survey, Data Lab now serves almost 100 TB of catalog data from all major NOIRLab-operated facilities, plus high-value external datasets (e.g. Gaia, unWISE/AllWISE, SDSS, and others). It also provides access to over 2 PB of images. As a science platform Data Lab combines big data holdings with a number of very useful data services, and with the powerful idea of remote analysis through a Jupyter notebook server. Data Lab user accounts come with a generous allocation of remote storage for files and personal databases. In this seminar I will introduce the concepts that underlie a science platform, and highlight the data services Data Lab is able to offer thanks to the co-location of big data and compute capacities. I will then discuss some of our current new developments, for instance to serve data products from massively-multiplexed spectroscopic surveys such as SDSS and DESI. Finally I would also like to discuss with everybody some of the challenges and pportunities for making science platforms more unified in terms of user experience, and more interoperable from the operators\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\' perspective. Time permitting, I can show a brief live demo of Data Lab.

On that day there will be no LIneA webinar. Corpus Christi is a public holiday in some countries, including Brazil.

Webinar LIneA .pdf

A Astronomia e ciências afins despertam o interesse da população, oferecendo um grande potencial de estimular jovens a ingressarem em carreiras científicas e despertarem o interesse por temáticas relacionadas. Dentro desse contexto, a divulgação científica pode exercer um importante e necessário papel de impulsionadora de novos talentos e de facilitadora entre ciência e sociedade, podendo inclusive possibilitar um primeiro contato com as ferramentas técnicas da área. Mas o que os jovens pensam sobre a ciência? E os comunicadores da ciência: o que pensam e pesquisam? Discutiremos essas e outras questões a partir de estudos acadêmicos e de dados do Instituto Nacional de Comunicação Pública da Ciência (INCT-CPCT), bem como de pesquisas nacionais e internacionais.

Supermassive Black Holes (SMBHs, masses of 10⁶ – 10⁹ M_Sun) inhabit the nucleus of most galaxies in the Universe. Although not even light can escape their event horizon, when capturing mass, they become the most efficient energy generators in the Universe via the emission of radiation, winds and jets by an accretion disk that surrounds them in active galactic nuclei (AGN). These are the so-called AGN feedback processes required by galaxy evolution models in order to reproduce the mass distribution of galaxies in the Universe. Nevertheless, the actual processes involved are not yet well constrained by observations. In this talk, I will discuss studies that provide constraints to these processes via MaNGA-SDSS observations of a sample of AGN and a matched control sample of non-active galaxies. These observations have been used to investigate answers to two of the most important questions on the relation between SMBHs and their host galaxies: (I) What are the necessary conditions for triggering/maintaining AGN in galaxies? (II) Which is the impact of the nuclear activity on the host galaxy and its environment?

francesco_valentino_2021-compactado.pdf

The majority of the stars in the local Universe belong to massive, red, spheroidal, old galaxies that died several billion years ago, ceasing their active formation of new stars. In our current view, these galaxies experienced an intense burst of growth immediately followed by a sudden death early in the history of the Universe, so that we routinely observe a numerous population of such dead cosmic giants already in place 10 Gyr ago at z~2 comfortably reproduced by many galaxy formation models and simulations. However, the coherent scenario that we have been building during the last 15 years has been recently shaken by the discovery of the existence of massive dead galaxies already at z~4, only 1.5 Gyr after the Big Bang. How is it possible to assemble 100 billion Suns in such a short time, given the expected theoretical limits on the sustainable star formation rate? What can we learn about such a dramatic production of stars? What are the progenitors of these quiescent galaxies at z>4? And why do these cosmic giants die so early in the history of the Universe? Here I will present the results of a spectroscopic campaign targeting massive quiescent galaxies at z~4. These include a compact system at z=4.01 with a measured stellar velocity dispersion fully consistent with z~2 objects, showing that quiescent galaxies can be remarkably mature also from a dynamical standpoint. The absence of nebular emission lines and the lack of far-infrared detections confirm a suppressed star formation. From the joint modeling of the spectra and the SEDs, we derive stellar masses of log(Mstar/Msun)~11, placing these galaxies >1-2 dex below the main sequence. Such modeling suggests that these sources experienced a strong (SFR~1200-3500 Msun/yr) and short (~50 Myr) burst of star formation in their past, properties reminiscent of the population of sub-mm galaxies (SMGs) generally indicated as candidate progenitors. We thus compare the comoving number densities and the expected properties of the progenitors of our and other samples in the literature with observations of z>4 SMGs. We find a fair agreement between these two populations only for the deepest sub-mm surveys detecting the most extreme starbursts, but also more normal galaxies. Exploring the Illustris-TNG simulation, we do retrieve populations of quiescent galaxies at z~3-3.5 with number densities and properties in rough agreement with the observations, but in increasing tension at higher redshifts. We find that not all the progenitors of z~4 quiescent galaxies in the simulation shine as bright SMGs in their past and, conversely, not all bright SMGs quench by z~3, supporting the observational evidence and suggesting the existence of different paths to form massive galaxies in the early Universe.

sdss4-linea-2021-05-07.pdf

I will discuss the recent work of the Sloan Digital Sky Survey on cosmology and galaxy evolution, based on the observations from its fourth phase, which completed its six year program on the morning of January 21, 2021. This spectroscopic survey mapped the Milky Way galaxy, ten thousand nearby galaxies, and finished the largest three-dimensional map of the universe to date. I will describe a sampling of what we have learned, focusing on: tests of the \\\\\\\"simplest\\\\\\\" model of the universe\\\\\\\'s expansion (which seems to be the right one); observations of star-formation and the flow of gas within galaxies; and on the formation history and migration of stars within our own galaxy.

In the era of large area, deep imaging surveys the ability to follow up even a small fraction of objects with spectroscopy is prohibitively expensive. As a result, these surveys will need to rely on other means to determine the distance to objects and turn the observed 2D sky into a fully three-dimensional map of the Universe using only the limited information available from broad band fluxes. In this talk I will discuss the challenges inherent in estimating redshifts for cosmology measurements in the Rubin Observatory Dark Energy Science Collaboration (DESC), which has extremely stringent requirements on knowledge of both individual galaxy redshifts and the redshift distribution of ensemble collections. I will discuss the end-to-end photometric redshift pipeline being developed by DESC, from simulated catalogs, to template and machine learning-based estimation algorithms, to systematic calibrations, that will enable the cutting edge science of the coming decade.

Proposito+LINEA_Webinar.pptx.pdf

No webinar, a empresa de comunicação Propósito dividirá aprendizados sobre a pesquisa e os workshops realizados com a comunidade científica junto ao LIneA durante o mês de Março de 2021, com as percepções em relação aos impactos e expectativas do uso de big data na astronomia brasileira, assim como as barreiras e expectativas para o futuro.

This workshop will bring together representatives of some of the more important data centers, eScience institutes and IT companies to discuss current solutions and new technological trends as data volumes from modern experiments such as LSST, Euclid and SKA continue to grow. The workshop will take place remotely April 13-15, 2021. Inquiries can be sent to workshop2021@linea.gov.br.

S_Avila_LIneA -compactado.pdf

Studies of the Large-Scale Structure via galaxy clustering is a fundamental observational pillar of the standard model of cosmology, LCDM. As we enter the era of sub-percent precision cosmology, we need to understand very well the connection between the dark matter halos and the observed galaxies ir order to obtain unbiased cosmological parameters. In this talk I will analyse all the assumptions that enter into the Halo Occupation Distribution (HOD) model to understand how they can affect the clustering of galaxies, with a focus on Emission Line Galaxies (ELGs), key to the next generation of experiments. I will study the shape of the mean halo occupation curves, the probability distribution function of the satellite galaxies and the position and velocity profiles of the satellite galaxies around the halo centers. Later, I will fit the HOD model to ELG data from the completed extended Baryonic Oscillation Spectroscopic Survey (eBOSS) under different assumptions. Finally, I will show what effect the galaxy-halo connection could have on cosmological constraints and will discuss its relevance in the context of future surveys such as Euclid or DESI.

KiDS-1000_Tilman_Troester.pdf

I will present the recent cosmological analyses of weak gravitational lensing observations from the Kilo-Degree Survey (KiDS-1000), with redshift-space galaxy clustering observations from the Baryon Oscillation Spectroscopic Survey (BOSS), and galaxy-galaxy lensing observations from the overlap between KiDS-1000, BOSS and the spectroscopic 2-degree Field Lensing Survey (2dFLenS). I will summarise the methodology and discuss the cosmological constraints, both within the the standard model of cosmology of a spatially flat Universe filled with cold dark matter and dark energy, and several extensions thereof. These results are then put in the context of the S8 tension: the disagreement between measurements of the cosmic microwave background by Planck and late-time analyses, such as ours, on how strongly matter in the Universe is clustered.

RioTESSv2.pdf

NASA’s Transiting Exoplanet Survey Satellite finished its primary mission and started its first extended mission on July Fourth, 2020. I will trace the history of the mission and the lessons we learned from Kepler and K2, ending with some of the recent highlights.

PLATO_talk_Linea.pdf

PLATO is a medium-class mission of ESA’s Cosmic Vision Program. It will address fundamental questions such as: How do planetary systems form and evolve? Are there other systems with planets like ours, able to develop life? The PLATO instrument consists of 26 small aperture telescopes providing a wide field-of-view and a large photometric magnitude range. It will target bright stars in wide fields to detect and characterize by photometric transit planets in the Habitable Zone down to Earth-size. Asteroseismology will be performed for the host stars to obtain unprecedentedly accurate stellar parameters, including masses and ages. Planet parameters accuracy are intended to be: 2%, 4-10% and 10% for planet radii, masses and ages, respectively. Up to 1,000,000 stars in about 50% of the sky will be observed and hundreds of small planets and thousands of Neptune to gas giants will be characterized, providing the first large-scale catalogue of bulk characterized planets with accurate parameters. The data will allow for the first time robust statistical analysis on physical characteristics of planets, of planetary formation, migration, architecture and evolution and its dependence on spectral type, metallicity and age of the host stars. Thirteen European countries and Brazil are participating in PLATO construction and scientific planning. Brazilian scientists of universities and research centers from all over the country are participating in the preparation of the PLATO mission. We will explore the satellite’s data mainly in the fields of stellar seismology, variable stars, white dwarfs, stellar rotation and exoplanets. Brazilian engineering is developing hardware and software components: a simulator for testing the image reading front-end electronics, photometric masks for imaging extraction, part of the altitude control system and jitter correction. We will give in this talk an overview of the PLATO mission and of the Brazilian participation.

slides_sunil_mucesh.pdf

Point estimates of galaxy properties determined with a small number of photometric bands are imprecise. To fully characterise uncertainties in the estimates, accurate probability distribution functions (PDFs) are required. These PDFs must also reflect the correlations between different quantities of interest. Traditionally, such PDFs are derived by fitting model spectra to photometric data. However, this approach quickly becomes impractical for fitting modern datasets, where sample numbers can exceed hundreds of millions. In this talk, I present a novel method based on the Random Forest (RF) machine-learning (ML) algorithm to generate accurate joint redshift-stellar mass PDFs. I discuss different techniques used to validate both the marginal and joint PDFs. Finally, I demonstrate GALPRO, a Python package capable of producing multivariate PDFs of galaxy properties on-the-fly at incredible speeds, and discuss some of its applications.

leanne_slides.pdf

Starting in 2023, the Vera C. Rubin Observatory will spend its first 10 years conducting the Legacy Survey of Space and Time (LSST). LSST will observe the entire visible southern sky and provide the widest, fastest and deepest view of the night sky ever observed. The resulting astronomical archive will be vast; 500PB of image data products and a 15PB final catalog of ~ 40 billion Objects. LSST will dramatically advance our knowledge in many fields including dark energy and dark matter, as well as galaxy formation and potentially hazardous asteroids. In this talk I give an overview of the Rubin Observatory and the Legacy Survey of Space and Time and talk about opportunities for early science and how to get involved.

The Legacy Survey of Space and Time (LSST), the first project to be undertaken at the new Vera C. Rubin Observatory, will be the most comprehensive optical astronomical survey ever undertaken. Starting in 2023, Rubin Observatory will obtain panoramic images covering the sky visible from its location in Chile every clear night for ten years. The resulting 60 petabytes of raw image data, essentially a digital color movie of the night sky, will include about 40 billion stars and galaxies, and will be used for investigations ranging from cataloging dangerous near-Earth asteroids to fundamental physics such as characterization of dark matter and dark energy. I will start the presentation with an overview of LSST science drivers and system design, and continue with a construction status report for Rubin Observatory. I will conclude with a brief discussion of a few Big Data challenges posed by LSST dataset.

We are proposing a 5-year public, wide-field, optical survey using an upgraded 20 square degree QUEST Camera on the ESO Schmidt Telescope at the La Silla Observatory in Chile - The La Silla Schmidt Southern Survey (LS4). We will use LBNL fully-depleted CCDs to maximize the sensitivity in the optical up to 1 micron. This survey will complement the Legacy Survey of Space and Time (LSST) being conducted at the Vera C. Rubin Observatory in two ways. First, it will provide a higher cadence than the LSST over several thousand square degrees of sky each night, allowing a more accurate characterization of brighter and faster evolving transients to 21st magnitude. Second, it will open up a new phase-space for discovery when coupled with the LSST by probing the sky between 12-16th magnitude - a region where the Rubin Observatory saturates. In addition, a Target of Opportunity (ToO) program will be able to trigger on Multi-Messenger Astronomy (MMA) events with localization uncertainties up to several hundred sq. deg. in multiple colors very quickly. This project has direct relevance to several cosmology and fundamental physics efforts including: peculiar velocity measurements, and hence fundamental constraints on general relativity, with supernova as standardized candles; gravitational wave standard sirens as probes of the expansion of the Universe and gravity; measurements of the Hubble constant through Type Ia and II-P supernovae; and probes of dark matter through low surface brightness galaxies and intra-cluster light.

The motions of galaxies on top of the Hubble expansion, peculiar velocities, are a probe of clustering and the growth of structure in the Universe. For distance indicators, peculiar velocities manifest themselves as residuals on the Hubble diagram. Ongoing and upcoming wide-field surveys measuring unprecedented numbers of distance indicators, together with improvements in the calibration of Type Ia supernova brightnesses, will provide exquisite precision in the mapping of the peculiar velocity field or more precisely the peculiar distance field. There is an international effort to organize follow-up resources to obtain redshifts, classifications, and distance measurements of transients from DESI, the Zwicky Transient Facility (ZTF), ZTF-II, and the Rubin Observatory in order to produce compelling constraints on the laws of gravity responsible for the growth of structure.

hatfield_talk.pdf

Deep wide-field surveys are important data sets for studying galaxy evolution over cosmic time, as both depth and width are needed for probing both sides of the knee of the stellar mass over a range of environments and redshifts. In this talk I will highlight work measuring galaxy environment via non-linear clustering in VISTA surveys as a function of stellar mass over 0.5 < z < 1.7 and modelling these measurements within the HOD phenomenology, in particular finding that environmental dependence of quenching only emerges at z ~1.5. We also measure the clustering of a sample of the most luminous LBGs at z ~6, finding that they are in the densest parts of the early Universe, supporting the claims in Bowler (2014, 2015) that this redshift is the onset of quenching. Collectively these results begin to put time constraints on when the main two pathways for quenching start operating. We validate our results Horizon-AGN, a hydrodynamical cosmological simulation with the volume and resolution necessary to compare with VIDEO and UltraVISTA. We find using mock catalogues that the known physics differences between Horizon-AGN and the real Universe are reflected in clustering measurements, and also study the impact of using photometric redshifts and stellar masses on conclusions. Finally I also highlight new developments in the use of machine learning for calculating photometric redshifts, using the ML code GPz code combined with template based methods.

LIneAWebinar_19112020.pdf

Elliptical (E) and spiral (S) galaxies follow tight, but different, scaling laws linking their stellar masses, radii, and characteristic velocities. Mass and velocity, for example, scale tightly in spirals with little dependence on galaxy radius (the “Tully-Fisher relation”; TFR). On the other hand, ellipticals appear to trace a 2D surface in size-mass velocity space (the “Fundamental Plane”; FP). Over the years, a number of studies have attempted to understand these empirical relations, usually in terms of variations of the virial theorem for E galaxies and in terms of the scaling relations of dark matter halos for spirals. We use Lambda Cold Dark Matter (LCDM) cosmological hydrodynamical simulations to show that the observed relations of both ellipticals and spirals arise as the result of (i) a tight galaxy mass-dark halo mass relation, and (ii) the selfsimilar mass profile of CDM halos. In this interpretation, E and S galaxies of given stellar mass inhabit halos of similar mass, and their different scaling laws result from the varying amounts of dark matter enclosed within their luminous radii. This scenario suggests a new galaxy distance indicator applicable to galaxies of all morphologies, and provides simple and intuitive explanations for long-standing puzzles, such as why the TFR is independent of surface brightness, or what causes the “tilt” in the FP. Our results provide strong support for the predictions of LCDM in the strongly non-linear regime, as well as guidance for further improvements to cosmological simulations of galaxy formation.

LIneA Seminar 2020-Carolina.pdf

In this talk, I will explore how scientific excellence can be a tool for development. Using the example of astronomy in South Africa, I will illustrate what major shifts have happened to stimulate science and technology, among others through the development and of a skilled workforce. I will draw examples from the Square Kilometre array project as well as other initiatives and I will describe how we plan socio-economic benefits in future projects.

Eigengalaxies.pdf

We demonstrate how galaxy morphologies can be represented by weighted sums of \\\\\\\\\\\\\\\"eigengalaxies\\\\\\\\\\\\\\\" and how eigengalaxies can be used in a probabilistic framework to enable principled and simplified approaches in a variety of applications. Eigengalaxies can be derived from a Principal Component Analysis (PCA) of sets of single- or multi-band images. They encode the image space equivalent of basis vectors that can be combined to describe the structural properties of large samples of galaxies in a massively reduced manner. As an illustration, we show how a sample of 10,243 galaxies in the Hubble Space Telescope CANDELS survey can be represented by just 12 eigengalaxies. We show in some detail how this image space may be derived and tested. We also describe a probabilistic extension to PCA (PPCA) which enables the eigengalaxy framework to assign probabilities to galaxies. We present four practical applications of the probabilistic eigengalaxy framework that are particularly relevant for the next generation of large imaging surveys: we (i) show how low likelihood galaxies make for natural candidates for outlier detection (ii) demonstrate how missing data can be predicted (iii) show how a similarity search can be performed on exemplars (iv) demonstrate how unsupervised clustering of objects can be implemented.

20201015 LIneA webinar.pdf

Blending of galaxies has a major contribution in the systematic error budget of weak lensing studies, affecting photometric and shape measurements, particularly for ground-based, deep, photometric galaxy surveys, such as the Rubin Observatory Legacy Survey of Space and Time (LSST). Existing deblenders mostly rely on analytic modelling of galaxy profiles and suffer from the lack of flexible yet accurate models. We propose to use generative models based on deep neural networks, namely variational autoencoders (VAE), to learn probabilistic models directly from data. We train a VAE on images of centred, isolated galaxies, which we reuse, as a prior, in a second VAE-like neural network in charge of deblending galaxies. We train our networks on simulated images including six LSST bandpass filters and the visible and near-infrared bands of the Euclid satellite, as our method naturally generalises to multiple bands and can incorporate data from multiple instruments. We obtain median reconstruction errors on ellipticities and $r$-band magnitude between $\\\\\\\\pm\\\\\\\\num{0.01}$ and $\\\\\\\\pm\\\\\\\\num{0.05}$ respectively in most cases, and ellipticity multiplicative bias of 1.6\\\\\\\\% for blended objects in the optimal configuration. We also study the impact of decentring and prove the method to be robust. This method only requires the approximate centre of each target galaxy, but no assumptions about the number of surrounding objects, pointing to an iterative detection/deblending procedure we leave for future work. Finally, we discuss future challenges about training on real data and obtain encouraging results when applying \\\\\\\\textit{transfer learning}. Our code is publicly available on GitHub.

Mapping the Milky Way and Beyond.pdf

The Legacy Survey of Space and Time [LSST] is an ambitious program undertaken at the Vera C. Rubin Observatory, which is presently under construction on the summit of Cerro Pachon in Chile. Within the LSST there are four main science themes: Understanding Dark Matter and Dark Energy Hazardous Asteroids and the Remote Solar System The Transient Optical Sky The Formation and Structure of the Milky Way The LSST Stars, Milky Way, and Local Volume [SMWLV] science collaboration is focused on that fourth theme concerning the past and present state of the Milky Way Galaxy and its neighbors. During this webinar we will explore the diverse working groups within SWMLV including their science goals and relationships across the broader community.

mireia_montes_lineA.pdf

There is a huge amount of astrophysical events that remain barely studied due to the lack of large, multiwavelength and deep surveys. These events are those which are very faint and extend over large areas of the sky. For instance, only a handful of galaxy clusters have been observed with enough depth to witness the intracluster light (ICL), a byproduct of interactions between galaxies in clusters. In the course of these interactions, individual stars are stripped from their galaxies and float freely, following the potential of the cluster and forming this diffuse light. Therefore, characterising the ICL is key to understanding the assembly mechanisms occurring inside galaxy clusters. Despite its importance, little is known about this light as it is very difficult to observe due to its low surface brightness. The availability of deep surveys, such as the Hubble Frontier Fields, have expanded our knowledge of the properties, and therefore the origin, of the ICL. In this talk, I will present the latest advances in our understanding of the ICL. I will also talk about the technical challenges of low surface brightness imaging and the possibility to explore the dark matter distribution in galaxy clusters by using this diffuse light.

Linea_webinar_2020_allison.pdf

A comprehensive understanding of galaxy evolution requires a holistic view into the anatomy of galaxies and the baryonic processes that shape their growth. Using a triad of properties—environment, mass, and time—I will present multi-wavelength studies of the extreme end of these parameters: the rare, dense regions of galaxy clusters; the most massive galaxies in the Universe; and the peak epoch of star formation. I will focus on the first spatially-resolved images and kinematics of molecular gas and star formation within high-redshift clusters, from infalling galaxies to the massive Brightest Cluster Galaxy (BCG) at the heart. Enabled by interferometric observations on the Atacama Large Millimeter Array (ALMA), I will highlight potential evidence for gas stripping and an unexpected channel for stellar mass growth in the centers of galaxy clusters at high redshift. With ALMA, this regime is burgeoning from case studies to a rich field of data science, allowing us to push further back in cosmic time and opening up the potential for many new discoveries.

des_mw_science_17_sep_2020_v1 .pdf

The stellar halo of the Milky Way represents only ~1% of the total stellar mass of our Galaxy, but is rich with clues regarding the formation history of the Milky Way, the properties of the first stars and galaxies, and the local distribution of dark matter. The current generation of wide-field optical/NIR imaging surveys including SDSS, DES, Pan-STARRS, Gaia, and HSC-SSP has allowed us to catalog more than a billion individually resolved stars out to the Milky Way viral radius and beyond with precise multiband photometry, proper motions, and light curves for variable stars. These datasets, in combination with follow-up spectroscopy, provide new perspectives on the dynamical and chemical history of the Milky Way and its satellites, and ever more stringent constraints on the fundamental nature of dark matter. I will discuss these topics, with a focus on recent results from the Dark Energy Survey (DES), a 5000 square degree imaging survey of the south Galactic cap to ~24th magnitude in the grizY bands.

AXS is a distributed system based on Apache Spark used for fast cross-matching of astronomical catalogs and for doing general analyses of astronomical data. In this talk, Petar will give a short introduction to Apache Spark and AXS and delve into inner workings of AXS and explain what makes it so fast. He will also show a live demo with several examples.

A diverse range of physical processes are responsible for regulating star formation across galaxies. Understanding their relative contributions to galaxy growth and quenching at different epochs is one of the key questions in galaxy evolution today. Since processes like mergers, winds, and feedback from supernovae and active galactic nuclei (AGN) are thought to have characteristic time-scales, identifying them and studying the strength of SFR fluctuations on these time-scales allows us to disentangle their relative contributions for a population of galaxies. In this talk, I will give a brief summary of current work focusing on (i) establishing a formalism to study the stochasticity of star formation at a given time-scale, (ii) analyzing a variety of cosmological galaxy evolution simulations using this formalism, and (iii) observational methods of reconstructing star formation histories, which yield constraints on the time-scales of galaxy growth, morphological transformations, and quenching. Taken together, simulations and observations leverage the predictive power against observational constraints to obtain a fuller picture of how galaxies evolve over time.

Greenplum2020 para LIneA.pdf

Análise de dados com grandes volumes de informação sempre foi um desafio computacional. Quando temos um volume de dados acima do que um computador consegue trabalhar de forma razoável temos que partir para soluções de computação distribuída que muitas vezes são complexas e pouco eficientes. O Greenplum Database é um banco de dados paralelo baseado em PostgreSQL que pode administrar petabytes de dados sem a necessidade de hardwares proprietários e com uma familiar interface SQL.

MattHiltonLink.html

The Atacama Cosmology Telescope (ACT) is a 6m telescope located high in the Chilean Andes that first began observations of the sky at millimetre wavelengths in 2007. Since 2016, ACT has been conducting a high-resolution cosmic microwave background survey over most of the southern sky, using its new receiver: Advanced ACTPol. In this talk, I will present the results of a search for galaxy clusters in all ACT data obtained up to 2018, using the redshift independent Sunyaev-Zel\\\\\\\'dovich (SZ) effect. This allows us to construct an effectively mass-limited cluster sample, and chart the growth of massive structures over the past 10 billion years, regardless of how distant the clusters are. We have assembled a sample of more than 4000 SZ-selected, optically-confirmed clusters with redshift measurements, reaching to redshift 2 - making this larger than all previous SZ-selected cluster samples to date. This was possible thanks to the overlap with new deep, wide area optical surveys such as the Dark Energy Survey, the Hyper Suprime-Cam Strategic Program, and the Kilo Degree Survey. I will give an update on our efforts to improve our knowledge of cluster mass calibration - which is needed to unlock the full statistical power of this cluster sample to constrain cosmological parameters - and briefly describe our follow-up with SALT and MeerKAT, aimed at topics related to galaxy evolution and extended non-thermal emission.

O processamento de grandes volumes de dados passou a ser a norma no suporte a pesquisas in-silico, como acontece com a eAstronomia. Neste webminar, discutiremos o framework Apache Spark que já vem se tornando uma referência de processamento Big Data. Apache Spark é integrado ao sistema de arquivos distribuídos HDFS para oferecer um ambiente de execução baseada em localidade de dados, com escalabilidade para grande número de nós de computação, e mecanismos de tolerância à falhas. O framework adota o modelo de processamento em memória reduzindo significativamente o custo evolvido em tarefas envolvendo iterações, muito utilizadas em processos baseados em aprendizagem.

HolisticModelsForClustersAndHalos_LineAwebinar_gue

Advances in cosmological hydrodynamics methods over the past three decades have ridden Moore’s law to establish rich predictive models for population statistics of the dark matter halos that host galaxies, groups, and clusters of galaxies. In this talk, I will first review evidence from multiple simulations teams, each incorporating custom recipes for AGN feedback, for common forms of galaxy occupation statistics — specifically the triad of total stellar mass, central stellar mass, and satellite galaxy count — conditioned on halo mass and redshift. The simulations generally support a multivariate Gaussian form for such features, and the anti-correlation of hot gas and stellar mass fractions seen in such models has recently been confirmed in lensing-mass conditioned statistics of the nearby LoCuSS cluster sample. I’ll close with efficient analytic forms to express multivariate cluster population statistics as halo mixtures to help motivate the coming future of multi-survey, multi-simulation analysis.

LSBG_Tanoglidis_Linea.pdf

Low-surface-brightness galaxies (LSBGs) are expected to dominate the galaxy population by number and may account for a significant fraction of the dynamical mass budget in the present-day Universe. They are observationally defined as galaxies with central surface brightness fainter than the night sky – thus, by definition, they are objects difficult to detect and study, especially across a wide sky area and different environments. In this talk, I will present the search for LSBGs in the Dark Energy Survey (DES), its challenges, and the resulting galaxy catalog - the largest such catalog so far. I will also touch upon the future directions in the LSBG searches, with a strong emphasis on the development of automated, deep learning-based, pipelines that will be extremely valuable in the advent of future surveys like the planned Legacy Survey of Space and Time (LSST) on the Vera C. Rubin Observatory

Exploding data volumes and velocities, new computational methods and platforms, and ubiquitous connectivity demand new approaches to computation in the sciences. These new approaches must enable computation to be mobile, so that, for example, it can occur near data, be triggered by events (e.g., arrival of new data), be offloaded to specialized accelerators, or run remotely where resources are available. They also require new design approaches in which monolithic applications can be decomposed into smaller components, that may in turn be executed separately and on the most suitable resources. To address these needs we present funcX—a distributed function as a service (FaaS) platform that enables flexible, scalable, and high performance remote function execution. funcX’s endpoint software can transform existing clouds, clusters, and supercomputers into function serving systems, while funcX’s cloud-hosted service provides transparent, secure, and reliable function execution across a federated ecosystem of endpoints. We motivate the need for funcX with several scientific case studies, present our prototype design and implementation, show optimizations that deliver throughput in excess of 1 million functions per second, and demonstrate, via experiments on two supercomputers, that funcX can scale to more than more than 130,000 concurrent workers.

LIneA Webinar 2020 - Ethan Nadler.pdf

As luminous tracers of the smallest halos, dwarf galaxies offer a unique window into the physics of dark matter (DM). The (lack of) a cutoff in the abundance of low-mass halos informs a variety of DM properties, which is crucial given the breadth of theoretical models that have gained popularity following the search for canonical WIMPs. In this talk, we describe recent advances in measuring and modeling small-scale structure tracers, focusing on the population of Milky Way (MW) satellite galaxies. In particular, we combine a state-of-the-art census of the MW satellite population with a rigorous model of the galaxy--halo connection in order to place the strongest astrophysical constraints to date on warm, interacting, and fuzzy DM. We discuss the implications of these constraints for specific DM candidates, including sterile neutrinos and ultra-light axions.

Simulations for Cluster-Based Cosmology.pdf

Observations of galaxy clusters have thus far supported the standard model of cosmology and provided constraints on non-standard models including evolving models of dark energy and modifications of gravity. The statistical power of galaxy clusters is at a golden age, where forthcoming observations will provide data for tens of thousands of galaxy clusters. However, our ability to further use clusters as probes is now limited by how well we measure cluster masses and quantify systematic effects in how we detect and measure galaxy clusters. To calibrate observations and understand underlying astrophysical processes, we need simulations that capture both those relevant astrophysical processes and the diversity within a large sample of galaxy clusters. I will discuss ongoing modeling efforts and software infrastructure development that allows us to best leverage the data in upcoming surveys.

LINEA_LGPD.pdf

A Lei Geral de Proteção de Dados (LGPD) altera significativamente o marco normativo referente à proteção dos dados pessoais mantidos por todas as organizações (empresariais e públicas). As corporações que já começaram sua jornada de conformidade têm encontrado inúmeras dificuldades para a construção de suas diretrizes de tratamento de dados pessoais e de políticas para prevenção e mitigação em caso de incidentes. A partir de uma abordagem interativa, analisarei nesta palestra as etapas para adequação à LGPD e as principais dores e desafios da jornada da conformidade. Abordarei um conjunto de diretrizes e boas práticas para proteção de dados que aliem técnicas de segurança cibernética, segurança jurídica e governança corporativa. -- The Brazilian General Data Protection Law significantly changes the regulatory milestone related to personal data protection, adopted by all public and private organizations. The organizations that have already initiated this compliance journey have come across many difficulties in building their guidelines for personal data treatment and preventing and mitigating security incidents. I shall analyze the steps for LGPD compliance and its main challenges from an interactive approach. I shall also discuss a group of best practices to protect personal data that align cybersecurity controls, legal security, and corporate governance. (This talk is in Portuguese)

JustinMyles_SOMPZ.pdf

Measuring the distribution of redshifts of galaxies observed by wide-field cosmology surveys like the Dark Energy Survey is an essential component to mapping the matter density field in three dimensions and thus understanding large-scale structure. This problem remains one of the key challenges to achieving state-of-the-art cosmology constraints from lensing surveys. In this talk I will describe sompz , a method for determining redshift distributions and show preliminary results from the application of this method to DES Year 3 data. I will discuss the importance of using deep, many-band photometric information to properly reweight the probability distribution of a set of known, reliable redshifts according to their prevalence in the wide-field survey samples from DES. I will present how Self-Organizing Maps are a flexible tool that facilitate this reweighting procedure by constructing photometric phenotypes that categorize each galaxy sample.

FrancoisLanusse.html

The upcoming generation of cosmological surveys such as LSST will aim to map the Universe in great detail and on an unprecedented scale. This of course implies new and outstanding challenges at all levels of the scientific analysis. In this talk, I will illustrate how recent advances in Deep Learning, and associated automatic differentiation tools (i.e. TensorFlow), can help us tackle these challenges and rethink our approach to data analysis for cosmological surveys. At the image level, combining physical models of the instrument (which account for noise/PSF) with deep generative models (which account for complex galaxy morphologies) can allow us to solve a range of astronomical inverse problems ranging from deconvolution to deblending galaxy images. At the cosmological analysis level, I will present our efforts to implement N-body simulations directly in TensorFlow, opening the door to a range of novel and efficient inference techniques.

Trans-Neptunian objects (TNOs) are remnants of the formation of the solar system, with their orbits, sizes and colors telling us their dynamical history. I will present an ongoing search for these objects using the Dark Energy Survey (DES), which covered 5000 sq. deg. of the sky between 2012 and 2018 in the grizY bands. Being a cosmology survey, the DES typically images each spot on the sky twice per filter per season, which makes the identification of moving objects challenging. The search, however, is feasible with the use of dedicated algorithms, and has yielded the detection of 316 objects in the first four years of data, with over one hundred newly discovered objects (Bernardinelli et al 2020a, ApJS, 247, 32). I will highlight some of the dynamical properties of these objects, including the sample of extreme TNOs in relation to the Planet 9 hypothesis, which predicts that such objects will be clustered in orbital space, an effect not seen in the DES data when observational biases are considered (Bernardinelli et al 2020b, arXiv:2003.08901). I will conclude by describing the status of the search in the full 6 years of data, where the catalogs are 0.4 mag deeper in completeness, at the expense of ~5x increase in source density.

CosmoDC2.pdf

CosmoDC2 is a large synthetic galaxy catalog designed to support precision dark energy science with the Large Synoptic Survey Telescope (LSST). The catalog is based on a trillion-particle, ($4.225$~Gpc)$^3$ box cosmological N-body simulation, the `Outer Rim\\\' run. It covers $440$~deg$^2$ of sky area to a redshift of $z=3$ and matches expected number densities from contemporary surveys to a magnitude depth of 28 in the $r$-band. Each galaxy is characterized by a multitude of galaxy properties including stellar mass, spectral energy distributions, broadband filter magnitudes, host halo information and weak lensing shear. We populate dark-matter halos with galaxies using a new hybrid technique that combines data-based empirical approaches with semi-analytic galaxy modeling. A wide range of observation-based validation tests has been implemented to ensure that cosmoDC2 has sufficient realism to enable the science goals of the analyses planned for the catalog.

PaulGiles.pdf

The XMM Cluster Survey (XCS) has analysed the entire XMM public archive with the primary aim of producing a large catalogue of X-ray selected clusters. To date, over 5,000 extended sources have been identified as clusters of galaxies. Most of those have associated redshift and X-ray temperature information. In this talk I will preview the second XCS data release and utilise recent DES data to describe a series of recent science results that include: the evolution and interpretation of various scaling relations (optical richness to T_x; L_x - T_x; M_x - T_x; velocity dispersion - T_x; M_lens - T_x; Y_sz - T_x); the evolution of the red sequence; constraints on modified gravity models. The talk will feature several joint XCS-DES (Dark Energy Survey) results, and outlooks for the future of cluster studies.

Looking Under the Hood of Identity Threat_LIneA.pp

Increasing national interest in science, technology, engineering, and math (STEM) domains has led to the largest STEM workforce of men and women in the U.S. However, despite current interest, women remain underrepresented. Studies examining the gender gap typically rely on behavioral measures, indexing the thoughts, feelings, and performance of stigmatized individuals in identity threatening STEM contexts. The present work highlights how looking beyond behavioral measures by indexing physiological, cognitive, and environmental factors provides essential insight into why the STEM gender gap remains and how individuals can increase diversity in STEM.

Carlos_Wuensche.pdf

Cosmology in the XXI century is experiencing a \\\\\\\"Golden Age\\\\\\\", with observations and theoretical models contributing to a large-scale description of the Universe. The current view is that it can be well described by the so-called Lambda-CDM model, but some open problems challenge physics and cosmology, including the origin and properties of so-called dark energy. The so-called baryonic acoustic oscillations (BAO), detected for the first time in 2005, are considered one of the most effective probes to understand the properties of dark energy. However, given the implications of these measurements, it is important that they are confirmed at other wavelengths and measured over a wide range of redshifts. The radio band provides a unique and complementary observation window, by emitting 21 cm of neutral hydrogen. The redshifted 21 cm (1420 MHz) emission of the hyperfine transition of neutral hydrogen is measured at lower frequencies, so that the observation frequency is converted directly into information about the source\\\\\\\'s redshift. The BINGO radio telescope (BAO from Integrated Neutral Gas Observations) is a new instrument, designed specifically to observe BAO, mapping a redshift band between 0.13 and 0.45. This seminar will present the basics of 21 cm BAO cosmology, the intensity mapping technique used and describe the current development status of the BINGO radio telescope.

The small bodies of the Solar System are a valuable tracer of its present-day structure, its evolution, and ultimately provide clues into the early times of its formation. In the next 5 years, the known sample of all small body populations will grow 10-50x, driven largely by large survey programs. For example, the LSST alone will generate a billion measurements of millions of Solar System objects, with simulations predicting ~100,000 new discoveries of nearby NEOs (Jones et al. 2017), 5.5 million for the main belt, and ~40,000-200,000 for the trans-Neptunian populations (Ivezic et al 2008; Juric et al. 2018). In this talk I will discuss what to expect from this sample, especially in the early years. I\\\'ll briefly overview the LSST and ZTF surveys, and what they are expected to discover (and -- in the case of ZTF -- already have discovered). The talk will discuss the techniques to find small bodies in survey datasets, and places where improved algorithms could significantly increase the yields. I will conclude with an overview the science opportunities this new sample is bringing.

O projeto ROSA tem como objetivo instalar e operar uma rede de telescópios robóticos de 40 cm de abertura, separados por distâncias de aproximadamente 100 km no sentido norte-sul. Inicialmente a rede está projetada para ter 50 telescópios e deverá ser instalada no território brasileiro. Um dos principais objetivos desta rede é a observação de ocultações de estelares por objetos do Sistema Solar com ênfase na região transnetuniana. Estas ocultações deverão ser previstas a partir do refinamento de órbitas obtidas pelas sucessivas observações do telescópio de 8.4 metros de abertura do LSST (Legacy Survey of Space and Time). As ocultações permitem a reconstrução da geometria dos corpos ocultadores e a detecção de possíveis atmosferas, satélites e anéis, informações estas que podem contribuir para o conhecimento da evolução do nosso Sistema Solar. Outro objetivo central da rede é funcionar como suporte para alguns dos 10 milhões de alertas que serão gerados pelo LSST em cada noite de observação. Finalmente, é importante destacar que ela terá um papel ativo no treinamento de estudantes e de futuros professores nas áreas de ciências. Os recursos para o projeto estão sendo solicitados junto a organizações privadas e públicas no exterior e no Brasil.

The availability of large data sets revolutionized many areas of scientific research, astronomy included. The current -- and in many ways already overwhelming -- data paradigm will suffer still another revolution with the advent of the new generation of large astronomical surveys. In this new scenario, the use of automated methods of analysis will be unavoidable. In this talk, I will give a short introduction to the basic principles of machine learning and describe situations where they are traditionally used in astronomical research. I will also present how domain knowledge can be used to optimize results from traditional algorithms by incorporating expert feedback in the learning process.

Spectroscopy and radiometry at mm/submm wavelengths has for a long time proven to be a powerful means to study the diversity of Solar System objects (planetary and satellite atmospheres, comets, airless bodies). The operation of ALMA as well as the upgrade of other facilities have provided many new observational results in recent years, addressing a wide range of topics related to either the origin/evolution of these bodies or to the physics of their environments. Submm spectroscopy of comets is a very poweful tool to study the molecular inventory and diversity of comets, their isotopic composition, the nature of cometary activity, the coma physics, and the asteroid/comet relationships. Spectroscopy of planetary atmospheres aims at determining the coupled fields of composition, thermal structure and dynamics, with implication on their energy budgets, and to characterize exogenous input to these atmospheres. Radiometry of satellites and airless small bodies (asteroids and trans-neptunian objects) constrains their surface thermal and emissivity properties, albedo, size, density, with implications for formation mechanisms (e.g. for binary systems). I will review some recent results from ALMA and other mm/submm facilities.

The Origins, Spectral Interpretation, Resource Identification and Security-Regolith Explorer (OSIRIS-REx) spacecraft of the NASA, arrived at the near-Earth asteroid (101955) Bennu in December 2018. Bennu is a primitive asteroid with a low albedo and is spectrally classed under the B-type asteroids, associated to organic-rich hydrated carbonaceous chondrites, that might harbour the pre-biotic chemical constituents, that were fundamental to the origin of life on Earth. The main objective of this space mission is to investigate Bennu using the suite of instrument aboard OSIRIS-REx, in order to select the most safely sampleable and scientifically appealing sample site, acquire loose regolith material from this site and deliver the sample safely to Earth in 2023, for more sophisticated analyses in the terrestrial laboratories. As of now, thorough analyses have led to identifying a primary sampling site as well as a backup site for sampling that is scheduled to take place in this summer. As such, the first results of the mission and a comparison with the knowledge we had about Bennu, prior to the arrival at the asteroid will be presented.

Usualmente, obstruções em frente aos espelhos de telescópios limitam a difração e dispersam a luz. Objetos de grande interesse científico como planetas e matéria circunstelar estão próximos a estrelas e frequentemente tem sua observação comprometida ou mesmo impedida pelo espalhamento de luz. É possível, no entanto construir um telescópio sem o suporte secundário e maximizar a faixa dinâmica.Tais telescópios são chamados fora-do-eixo. Eles podem ter contraste muito superior, porque não há obstruções no feixe, como suportes do espelho secundário. Sem obstruções eles permitem observar objetos próximos a estrela.Nessa palestra falaremos sobre o telescópio PLANETS (acronismo em inglês para Luz Polarizada de Atmosferas de Sistemas Extra-Terrestres Próximos), será um telescópio fora-de-eixo de 1,85m de diâmetro que combina várias novas tecnologias e técnicas de instrumentação. Ele será construído em Haleakala, um vulcão de 3.048 metros, na ilha de Maui, Havaí, com “seeing” e clima excelentes.Este telescópio será ideal para coronografia e outras técnicas que requerem um caminho óptico estável. A capacidade única deste telescópio permitirá avanços no estudo de ambientes circunstelares, objetos do sistema solar, atmosferas planetárias, atmosferas de exoplanetas e para o desenvolvimento da instrumentação inovadora. As instituições parceiras são a Universidade Estadual de Ponta Grossa(Brasil), Universidade Tohoku (Japão) e o Instituto Kiepenheuer para Física Solar (KIS, Alemanha).

Thanks to the combined information of baryon acoustic oscillations (BAO) and redshift-space distortions (RSD), anisotropic clustering measurements can probe simultaneously the expansion history of the Universe and the growth of density fluctuations, offering in this way one of the most promising routes to understand the origin of cosmic acceleration. In this talk, I review the standard methodology to obtain these measurements and their information content, using the final results from the Baryon Oscillation Spectroscopic Survey (BOSS) as an example. I also discus the problems and misconceptions caused by the common practice of expressing cosmological measurements in units of Mpc/h.I will discuss how these units has caused critical misconceptions for both the so-called sigma_8tension regarding the consistency between low-redshiftprobes and cosmic microwavebackground data, and the way in which growth-rate estimates inferred from RSD analysesare commonly expressed.

This talk will review the current state of dark energy research and in particular The Australian Dark Energy Survey’s program to measure spectra of tens of thousands of galaxies, thousands of supernovae, and time-lapse spectroscopy of almost 800 AGN. We’ll discuss what we need to do to distinguish between different models of dark energy and prospects of doing that in the next generation of surveys.

For over a hundred years, the Milky Way has been the nexus between many fields of astrophysics, linking together investigations into the formation of planetary systems and stars to studies of galactic evolution, cosmology, and astroparticle physics. Obtaining a detailed understanding of our Galaxy’s structure, formation, and evolution is therefore crucial to the advancement of the whole of astrophysical knowledge. Long thought to be a simple spiral galaxy with a simple disk-plus-bulge structure leading a relatively unperturbed life, the advent of large surveys such as SDSS, Gaia, and soon LSST has breathed new life into the field of galactic structure. I will discuss the new view of the Milky Way—complex, dynamic, and very much in the process of evolving—and what it implies about galaxy formation, galaxy evolution, and the nature of dark matter.

Joseph_Masiero.pptx

The NEOWISE infrared space telescope has provided an unprecedented set of infrared photometry and astrometry of the entire sky. This includes stars and galaxies, as well as over 150,000 asteroids and comets in our Solar system. I will provide an overview of the data that are publicly available, the tools and techniques that are included to access this data, and some of the results that have been derived from these measurements.

The Las Cumbres Observatory operates a global network of fully robotic telescopes with a range of instrumentation through a highly adaptable scheduler system. This scheduler makes it possible to coordinate a wide range of astronomical observations across multiple sites, telescopes and instruments, making it possible to seamlessly compensate in cases of poor weather. The rapid response of the scheduling system combined with the multiple sites makes the network ideal to respond quickly to a range of phenomena over many timescales from minutes to years. Distinct from other telescope networks in astronomy, LCO is a general-purpose facility which supports a wide range of science. I will give an overview of how the network operates, and the unique science that it makes possible. I will describe how the current Key Projects at LCO exploit the network\\\'s capabilities and the tools they use. Finally, I will end by looking to the future, and outline LCO\\\'s role as a partner in the Astrophysical Events Observatories Network.

Ardis_Herrold.pptx

We will discuss the philosophy and goals of the formal education program for LSST, and how this translates to the choice of our audiences and topics and design of our classroom investigations. Strategies for testing of the materials, and professional development will also be included as time allows.

Luccas_Secco.pdf

The cosmology analyzes of the Year-3 (Y3) data from the Dark Energy Survey (DES) is at full speed ahead. Our preliminary weak lensing sample contains 120 million objects over 4200 square degrees of sky and is the largest shape catalog to date. This statistical power comes at a price: the cosmic shear measurements are more sensitive not only to the signal but also to potential systematics. In this talk, I will present our prospects for the 2-point cosmic shear cosmology analysis and some of the leading systematics that must be under control, in particular the Intrinsic Alignment of galaxies. Additionally, I will talk about a preliminary detection of a shear 3-point correlation in the DES-Y3 simulations and data which is unprecedented in weak lensing surveys.

Spectroscopic surveys provided a unique opportunity to explore the large-scale structure in the Universe, in particular they have been conceived to study one of the most important questions of modern cosmology: the nature of dark energy. During this seminar I will review three spectroscopic surveys: BOSS, eBOSS and DESI.In the first part I will explain the observables that we can use to learn dark energy: the Baryons Acoustic Oscillations(BAO) and the Redshift Space Distortions (RSD). In the second part, I will focus to present the latest eBOSS results from the full shape analysis that includes de Redshift Space Distortions as well as the Alcock Paczinsky parameters with the Luminous Red Galaxy sample Data Release 14. In the third part I will present how we can use galaxy redshift surveys to explore other physics than dark energy, in particular to constrain properties of neutrinos. Neutrinos were a dominant component of the energy density in the early universe and, therefore, played an important role in the evolution of cosmological perturbations. In particular neutrinos imprint a temporal phase of sound waves in the primordial plasma. I will present the first constraint on this neutrino-induced phase shift in the spectrum of baryon acoustic oscillations of the BOSS DR12 data.

The National Optical-Infrared Astronomy Research Laboratory (formerly NOAO) started the Teen Astronomy Cafés program to excite the interest of talented youth in STEM. One Saturday a month during the academic year, high school students interact with expert astronomers who work with big data. Students learn about killer asteroids, exoplanets, lives and deaths of stars, variable stars, black holes, the structure of the universe, gravitational lensing, dark matter, colliding galaxies, and more. The format for the cafés is a short presentation by an astronomer, a computer-based lab activity and a discussion during lunch. Presently, 50% of the students are from schools with failing grades (by the Arizona Department of Education). Over 50% are girls. Our science cafés demonstrate that scientists play a key role in increasing student interest and curiosity about science research and in helping students get a sense of scientists as people. The cafés also demonstrate that scientists can help students see how research connects with issues important to society and with students’ daily lives.

Julian_Bautista_31102019.pdf

Desde mais de 20 anos, o Sloan Digital Sky Survey (SDSS) vem produzindo os maiores mapas em 3D do Universo usando espectroscopia. Com o último projeto cosmológico do SDSS -- o extended Baryon Oscillation Spectroscopic Survey (eBOSS) -- foi possível estudar a estrutura em grande escala e obter as melhores medidas de expansão do Universo em função do tempo até hoje, em redshifts desde 0.6 até 2.3. Os resultados finais do eBOSS serão publicados no começo de 2020. Aguardando as medidas finais, irei apresentar as principais medidas publicadas usando a metade dos dados (Data Release 14). Uma parte deste webinar será dedicada a mostrar o estado atual da seguinte geração de levantamentos espectroscópicos para cosmologia: o Dark Energy Spectroscopic Instrument (DESI), cuja primeira luz ocorreu na semana passada.

Matteo_Costanzi.pdf

The abundance of galaxy clusters has the potential to be a powerful tool for constraining cosmological parameters, provided we can rely on well calibrated mass-proxies to estimate the cluster masses. In this talk I will present the cosmological analysis we performed using the optical cluster catalog extracted from in the Dark Energy Survey Year 1 data. The DES Y1 data is based on optical/near-infrared imaging covering ~1800 square degrees of the southern sky, taken from August 31, 2013 to February 9, 2014 by the Dark Energy Camera mounted on the 4-m Blanco telescope at Cerro Tololo Inter-American Observatory in Chile.In particular, I will introduce the different ingredients necessary to perform a cosmological analysis of cluster abundance, lingering on the systematics which mostly affect photometric cluster catalogs. Thus, I will present preliminary results obtained from the analysis of DES Y1 cluster abundance data and weak lensing mass estimates, discuss current problematics, and conclude with future perspectives.

The Large Synoptic Survey Telescope (LSST) will create the largest census of the Universe ever undertaken, repeatedly surveying the sky every few nights for ten years. The potential for scientific discoveries with the LSST will be limited only by how well we can extract the knowledge contained in its massive and complex data streams. The mandate of the Large Synoptic Survey Corporation (LSSTC) is to maximize the scientific output from LSST with investment in the international research community. Indeed, as first light and full operations approach, LSSTC is ramping up its support for LSST science. I will review highlights from a year of activities we have funded, and describe our very ambitious plans for helping the community tackle the scientific, software, and statistical challenges associated with LSST during the next few years. You can directly benefit from these programs, with researchers from LSSTC member institutions guiding how funds are allocated and receiving the highest level of benefits.

Matias_Carrasco_10102019.pdf

In this talk, I will review the basic concepts of Kubernetes and how these are being applied within the context of Astronomy. In particular, Kubernetes has been already adopted by surveys like DES and LSST and is slowly making its way into other projects. I will do a live demo of a simple deployment and how this can be expanded into a full production-like system.

I will present the stage-IV Dark Energy Spectroscopic Instrument (DESI). The scientific goals of DESI on dark energy, redshift space distortions, inflation and neutrino mass will be compared to current measurements and limits set by ongoing experiments, in particular by the SDSS BOSS and eBOSS projects. I will then present the construction status of DESI, which is nearing completion, and give the timeline of the five-year survey. With first light quickly approaching, we expect DESI to be one of the world’s best facilities for wide-field spectroscopy throughout the decade.

By using simulations, we have studied the stability of an isolated thin exponential stellar disc embedded in a static spherical NFW halo and explore how the disc\\\'s mass and size (relative to the halo) together with the concentration of the halo itself affect the mass of the pseudobulge that forms (if any). We observe a transition from Scd to Sab and barred morphologies when the mass of the disc grows (relative to the mass of the halo), when the size of the disc is reduced, and when the concentration of the halo is lowered. The final bulge-to-total stellar mass ratio B/T is strongly related to the disc\\\'s fractional contribution $f_{\\\\rm d}$ to the total gravitational acceleration at the optical radius. The formula $B/T=0.5f_{\\\\rm d}^{1.8}$ fits the bulge-to-total stellar mass ratios that we measure in our simulations to an accuracy of $30\\\\%$ and reproduces the observed morphology -- luminosity relation. Our formula will be useful to improve the description of pseudobulges in future semianalytic models of galaxy formation.

Pedro_Beaklini.pptx

Pedro P.B, Beaklini (IAG/USP), Tânia P. Dominici (MAST/MCTIC), Zulema Abraham (IAG/USP), Juliana C. Motter (IF/UFRGS) Blazars are high luminosity AGNs presenting relativistic jets seen at small angles to the line of sight. They are also characterized by variability across the entire electromagnetic spectrum, and the emission is boosted due to relativistic effects. In this talk, I will present observations carried out at 43 GHz (7 mm) for the blazars 3C 273, 3C 279 and PKS 1510-089 using the Pierre Kaufmann Radio Observatory (former Itapetinga). I will report on the variability monitoring results of theses sources and how they correlate with other wavelengths. Delays between high energy emission, either gamma-rays or optical R band, with respect to the 7-mm light curve have been detected. Although such delays present different observational signatures for each source, they are well explained by the shock-in-jet model. A high frequency follow up monitoring program of blazar sources using the LLAMA (Long Latin America Millimeter Array) Observatory is being planned. LLAMA is a joint initiative between Brazil and Argentina. In this presentation, I will also summarize the current status of the LLAMA and Pierre Kaufmann observatories.

Robert_Gruendl.pdf

Nesta sessão será apresentada como é feita a redução de imagens e os diversos produtos criados neste processamento.

Kate_Grier.pdf

The Sloan Digital Sky Survey Reverberation Mapping Project (SDSS-RM) has completed its first six years of spectroscopic observations of a sample of ~850 quasars with the SDSS-III BOSS spectrograph. From January-July in 2014-2019 more than 80 epochs of spectroscopy were obtained for this quasar sample, and supporting photometric observations were also carried out at the Canada-France-Hawaii Telescope and the Steward Observatory Bok telescope. I will present a status update on the SDSS-RM program, focusing specifically on recent reverberation mapping results from the wider 850-quasar sample using four years of combined photometric and spectroscopic data. In particular, we recently reported measurements of the CIV emission line in 52 quasars at redshifts ranging from z = 1.5 - 3. Our work has increased the previous sample size of reverberation-mapped active galaxies by about a factor of four, and represents the first large sample of high-redshift CIV reverberation mapping observations beyond the local Universe.

Sugata_Kaviraj.pdf

Low-surface-brightness (LSB) galaxies, a heterogeneous population ranging from dwarfs to large, diffuse spirals, are faint systems that are largely invisible in past surveys (e.g. the SDSS). However, LSB galaxies dominate the local number density and understanding their formation is central to a complete understanding of galaxy evolution. Using a cosmological hydro-dynamical simulation, we explore how these systems form and why they diverge so strongly from their high-surface-brightness counterparts over cosmic time. We show that, at high redshift (z~3), LSB progenitors have stronger, burstier star formation. The resultant stronger stellar feedback flattens their gas-density profiles, by displacing cold gas (but does not quench star formation). These flatter gas profiles, in turn, produce flatter stellar systems, which are more susceptible to tidal processes. Over time, heating and stripping due to the ambient tidal field drive rapid (cold) gas loss and a strong increase in effective radii, that produces today’s LSB systems. In clusters, ram-pressure stripping provides an additional mechanism that assists in this evolution (although tidal heating/stripping remains the principal mechanism of LSB galaxy formation even in these ultra-dense environments). The LSB Universe is a new frontier in the study of galaxy evolution and offers a vast, untapped discovery space that is perfectly aligned with the capabilities of new surveys like the Hyper Suprime Cam SSP and, in the near future, LSST.

Edward_Schlafly.pdf

The interstellar medium (ISM) is the fuel of star formation, and its scattering and absorption of light transforms the Galactic radiation field. Despite its importance, most observations of the Milky Way\\\\\\\'s ISM are limited to two dimensions; its angular distribution is precisely measured, but its distribution in distance is much more uncertain. Large surveys of stars can be used to resolve this uncertainty. Because light from stars is absorbed and scattered by intervening material before observation on earth, the Galaxy\\\\\\\'s stars can be used as a dense network of lighthouses, effectively x-raying the ISM to reveal its 3D structure and properties. In this talk, I\\\\\\\'ll describe our ongoing program to use large surveys to map the ISM in 3D. We have mapped the density of dust in the ISM over the nearest 5 kpc at unprecedented resolution, highlighting complex networks of diffuse voids and dense star-forming regions. We have also been able to measure the size distribution of dust grains throughout the Milky Way, revealing kiloparsec-scale structures that may track variations in the Galactic star-formation rate and gas density. Numerous other projects are possible, ranging from studies of the 3D kinematics of the ISM to the Galactic magnetic field. New surveys and instruments like Gaia, SDSS-V, LSST, and JWST promise a bright future for 3D studies of the ISM, offering incredibly accurate distance measurements, order-of-magnitude larger samples of stars, and unrivaled sensitivity.

Joe_Zuntz.pdf

DESC is the cosmology collaboration for LSST, the Large Synoptic Survey Telescope, which is currently under construction at Cerro Panchon, Chile. Much of DESC\\\\\\\\\\\\\\\'s work is computational, requiring large data processing facilities and tools. I will discuss DESC\\\\\\\\\\\\\\\'s current plans for workflow and processing, starting from the catalogs provided by data management and ending with cosmological constraints

Bryan_Miller.pdf

Time domain and multi-messenger astrophysics are rapidly growing and important modes of observational astronomy. The commissioning of LSST and the increasing sensitivity of facilities such as LIGO and IceCube mean that both rapid-response and long-term flexible scheduling capabilities will be essential. Significant effort by a variety of groups is being put into developing the components of a follow-up system for dynamically turning survey alerts into data. This system consists of: 1) brokers that will aggregate, classify, and filter alerts; 2) Target Observation Managers (TOMs) that are used by science teams for prioritizing targets and managing observations and data; and 3) observatory interfaces, schedulers, and facilities along with data reduction software and science archives. These tools will also be beneficial to all users of these facilities. This presentation will review the current status of this developing network with emphasis on the efforts of the Astronomical Event Observatory Network (AEON), a collaboration between Las Cumbres Observatory, NOAO/SOAR, and Gemini, and outstanding issues will be discussed.

Weak lensing by large-scale structure is one of the most promising techniques to learn more about the nature of dark energy by mapping the dark matter distribution in the Universe as a function of distance. Weak lensing has also developed into the main tool to determine the masses of collapsed structures, from clusters to galaxies, enabling new studies of scaling relations. I will review the recent progress in this active area of research and discuss the prospects for future projects, such as Euclid.

Françoise_Combes.pdf

Recent molecular line observations with ALMA in several nearby Seyferts have revealed the existence of molecular tori, and the nature of gas flows at 10-20pc scale. At 100pc scale or kpc-scale, previous work on gravitational torques had shown that only about one-third of Seyfert galaxies experienced molecular inflow and central fueling, while in most cases the gas was stalled in rings. At higher resolution, i.e. 10-20pc scale, it is possible now to see in some cases AGN fueling due to nuclear trailing spirals, influenced by the black hole potential. This brings smoking gun evidence for nuclear fueling. In our sample galaxies, the angular resolution of up to 80mas allows us to reach the BH-zone of influence and the BH mass can be derived more directly than with the M-sigma relation.

Alexandre_Le_Tiec.pdf

The era of gravitational-wave astronomy was opened in 2015 with the first direct detection by LIGO of gravitational radiation emitted during the coalescence of two 30 Solar mass black holes. The planned Laser Interferometer Space Antenna (LISA) will detect gravitational waves generated during the coalescence of supermassive black hole binaries and the inspiral of stellar mass compact objects into massive black holes. I will present the first fully relativistic study of gravitational radiation from bodies in circular equatorial orbits around the massive black hole at the Galactic Center, Sgr A*. The signal-to-noise ratio in the gravitational wave detector LISA, as well as the time spent in LISA band, have been evaluated for main-sequence stars, brown dwarfs and compact objects. I will argue that Sgr A* is a valuable target for LISA.

Chihway_Chang-compressed.pdf

Modern cosmology is built on a robust foundation termed the ΛCDM model. The ΛCDM model has been remarkably successful — it is able to explain a large range of observational data with only six parameters. There are, however, unresolved questions that leave cosmologists unsatisfied: What is Dark Matter? What is Dark Energy? With the increasingly powerful data, is ΛCDM still internally consistent within multiple cosmological probes? In this talk I describe a program where we seek to answer these questions using information in the large-scale structure, as recorded by state-of-the-art cosmological surveys. I will focus on a series of analyses using two-point functions of different cosmic fields and describe ongoing work to go beyond the standard two-point framework.

Hector_Gil-Marin.pdf

In this talk, I will present an introduction on the concepts of redshift space distortions (RSD) and Alcock-Paczynski (AP) effect and their applicability to measure cosmological parameters, such as the growth of structure or Omega_m, from large scale structure spectroscopic galaxy surveys. As an example, I will present such analyses for BOSS and eBOSS surveys and will review some of the future results for DESI, including both the power spectrum and bispectrum techniques.

Marika_Asgari.pdf

The Kilo Degree Survey (KiDS) is a purpose-built gravitational lensing survey with high quality images and a wide photometric coverage, resulting in very high fidelity data. This dataset, therefore, provides an excellent playground where we can test our methods in preparation for future weak lensing surveys. Already the first KiDS data release (KiDS-450) shows a mild tension with CMB results, which has sparked both skepticism and excitement within the community. One of the major challenges for cosmic shear is the treatment of systematics in the data. Marginalised systematics, currently, comprise a significant portion of the error bars on the estimate of the amount of structures (S_8) inferred from the data. In this talk, I will focus on cosmic shear analysis of the latest KiDS data and compare the cosmological results given different two point statistics and I will go through complications that arise in this kind of analysis and the effect of systematics on the data. I will finally show results from the combination of KiDS and DES cosmic shear data.

Dwarf galaxies are the most common type of galaxy in the Universe and include the most dark-matter-dominated objects known. They offer intriguing insights into evolutionary processes at low halo masses and low metallicities. Moreover, as survivors of a once much more numerous population of building blocks of larger galaxies, they are key to understanding very early star formation processes. The Local Group and particularly the Milky Way\\\'s dwarf galaxy entourage offer us the unique possibility to compare in detail dwarf and Galactic populations. This is an important step towards quantifying the magnitude and time scales of dwarf contributions to the build-up of the Milky Way and allows us to test predictions of cosmological theories and hierarchical structure formation.

Fabian_Schmidt.pdf

The large-scale clustering of galaxies contains a wealth of information on the geometry and expansion history of the universe, on gravity, and on the initial conditions. In order to extract this information, we need to deal with the complex formation process of galaxies. As a result, current observational constraints are largely based only on the robust BAO feature. However, thanks to significant advances in o ur theoretical understanding of galaxy clustering, we now have a well-defined approach for absorbing all the complicated, incompletely understood physics of galaxy formation into a set of free parameters (the bias parameters and stochastic amplitudes), which opens up considerable additional constraining power. The next challenge to tackle then is how best to connect this theory with data, as delivered by ongoing and future surveys such as BOSS, DESI, and Euclid. In my talk, I will review these developments, and discuss the prospects galaxy clustering as a robust probe of cosmology in the coming decade.

Katelyn_Stringer.pdf

RR Lyrae variable stars (RRL) are powerful distance indicators which can be used to locate stellar structures within the Milky Way halo. The Dark Energy Survey (DES), with its large observing footprint and depth, presents a rich opportunity to discover these variables to distances near the edge of the Galactic halo. However, the small number of observations in the DES wide-field survey data (fewer than 20 multiband observations over the first three years) pose a challenge for the traditional RRL detection techniques. In this talk, I will describe the multiband template fitting method and machine learning classifier we developed to identify 5783 RRL candidates in the first three years of DES data. These methods will enable RRL detection in other sparse multiband data sets that are not optimized for time series analyses.

The orbital structure of the Kuiper Belt is dynamically excited, with most objects found on highly inclined and eccentric orbits. It is this orbital structure that has provided the main evidence for the early migrations of the gas-giant planets, and the violent dispersal of the outer proto-planetesimal disk. Many observational properties have been used as constraints on numerical efforts to uncover the details of the migratory history, including the detailed orbital distribution of Kuiper Belt Objects (KBOs), and the compositional classes KBOs which are known to correlate with the different orbital classes in which KBOs reside. This chemo-dynamical structure appears to be the result of the dynamical processes experienced by KBOs during the dispersal of the early disk, and the compositional heterogeneity of that disk. As a dynamical tracer however, the chemo-dynamical structure of the Kuiper Belt remains largely untapped. It was around this idea that the Col-OSSOS project was created. The Colours of the Outer Solar System Origins Survey is a large program executing on the Gemini-North and CFHT telescopes aimed to gather high quality optical-NIR colours of ~100 KBOs, in a brightness complete sample, and has designed to overcome various weaknesses of colour surveys that came before it. Col-OSSOS has been running since 2014 and has resulted in many exciting findings to date. With some anecdote about working very closely with Gemini and the excellent work they have done, I will present some of the main results of the Col-OSSOS, including a discussion about what the observed colour distribution informs us of the chemical structure of the early disk. Our results have provided some critical context for a number of otherwise curious objects, including an asteroid found in the Kuiper Belt, Phoebe’s unusual surface, and some odd blue binary KBOs found where no blue objects should be. I will conclude with a cosmogonic history that draws all of these disparate pieces together.

Bruno_Castilho.pdf

Nas últimas duas décadas a astronomia optica e infravermelha do Brasil teve um grande crescimento, tanto em número de pessoas quanto em publicações e isto reflete no reconhecimento internacional de nossa comunidade. Este crescimento foi alavancado em boa parte pelo maior acesso a novos telescópios e instrumentação, seja no país seja por acordos internacionais. Em 2020 e 2021 vencem os atuais acordos do SOAR e do Gemini e fazem 10 anos do workshop promovido pelo LNA para avaliar a questão da infraestrutura observacional. Quais são os desafios científicos para a nova década e o que nossa comunidade precisa em termos de instrumentação para poder participar ativamente das respostas a estes desafios? Neste seminário não trazemos as respostas prontas a estas questões, mas sim levantamos a discussão e os pontos a serem discutidos para que toda a comunidade possa participar.

Paola_Dimauro.pdf

Passive and star forming galaxies have different morphology and structure, suggesting a link between the star formation activity and the formation/growth of internal components. Despite the numerous efforts, the details of how galaxies form and evolve, and in particular the mechanisms responsible of the decreasing/cessation of the star formation and the morphological transformations are still not fully understood. In the talk I will present results we obtained combining the morphology and the star formation activities for galaxies in the CANDELS survey. We first studied structural properties of the four main morphological classes (bulge dominated systems, pure spiral disk dominated, intermediate 2-component and irregular disturbed galaxies) and how their fractions change at different epochs (Huertas-Company et al,2016) to then move forward and analyze in more details the galaxy structure exploring bulge and disk properties and how they correlate with the morphology or the star formation activities of the host galaxies (Dimauro et al, 2018, 2019).

Hao-Yi_Wu.pdf

The acceleration of the Universe is one of the biggest puzzles in physics: is it due to a cosmological constant, dynamical dark energy, or modification of gravity? Galaxy clusters provide a unique opportunity to answer this question. In this talk, I will first discuss how we use cluster abundances to constrain cosmic acceleration, and how weak gravitational lensing effects play a key role in constraining cluster mass. I will then present my research on using simulations to understand cluster weak lensing signals and to accurately model covariance matrices. These results not only mitigate the systematic errors in current cluster surveys but also help the optimization of future ground- and space-based missions.

LINEA_Webinar_MWFitting.pdf

In this webinar I will talk about the results of the MWFitting pipeline applied to the stellar content of the DES-Y3 Gold internal release, in a paper about to be published. We fit the thick disk and halo of the Milky Way, simulating the Galaxy with a combination of TRILEGAL models. The stellar density of the thick disk is modeled with an exponential dependence in the radial and vertical directions, and the halo is described as an oblate model with the density of stars decreasing following a radial power law. The pipeline shows robust parameters for those components and the residuals from photometric comparisons attest the excellent job of the method. I detailed the methods applied in the pipeline, the implications of the results, also regarding the upcoming surveys and finally preliminary outcomes with other surveys.

Jennifer.pdf

Numerous international astronomy reports have recently highlighted the need for fully dedicated, large aperture, massively multiplexed spectroscopy in the optical and near-Infrared wavelength regimes. Such a facility is the most obvious missing link in the emerging network of ground-based observational facilities world-wide. The Maunakea Spectroscopic Explorer (MSE) is a planned 11-m telescope facility designed to fill this scientific gap. MSE is completely dedicated to multi-object optical and near-Infrared spectroscopy of samples of between thousands and millions of astrophysical objects at a range of spectral resolutions. In this talk I will overview the wide-ranging scientific capabilities of the MSE project and review the current design status of this next generation observatory.

Wood-Vasey_LSST_DESC_LIneA.pdf

The Large Synoptic Survey Telescope will open new frontiers in large-scale data analysis in astronomy. In this talk I will discus the opportunities and current implementation of data access and analysis in the LSST Project and in the Dark Energy Science Collaboration. The LSST Science Platform is being built to enable the LSST community to explore the rich and large datasets from from LSST. While the LSP may not be fully operational until the beginning of the LSST Operations in late 2022, development and prototyping efforts are currently underway to understand both the technical scope and user interactions with this ambitious platform. In parallel to the LSST Project construction efforts, the wider LSST scientific community is preparing for LSST. In particular, the Dark Energy Science Collaboration (DESC) was formed to fully exploit the ability of LSST to determine the nature of dark energy. In advance of data from LSST, DESC is preparing a series of Data Challenges to develop and verify scientific and basic data processing pipelines. These data challenges are helping both DESC and the LSST Project explore and understand the opportunities and challenges of exploring terabyte-scale image datasets with catalogs with billions to trillions of entries.

Brian-Yanny .pdf

We present details of the Balrog object injection and (re)measurement code which is used by DES to determine completeness and biases in detection and measurement of faint stars and galaxies.

George_beckett.pdf

The Large Synoptic Survey Telescope promises to revolutionalise many aspects of optical astronomy, most notably dealing with the transient universe. UK-based astronomers have a particular opportunity, since the UK is part of several other significant facilities on a similar timescale--for example, Euclid, 4MOST, and SKA--yielding a possibility to secure leadership in a number of areas, including dark energy, solar system science, and transients. Recognising this, the UK community has formed a consortium with representation from every UK-based astronomy group, to encapsulate its ambitious plans for LSST and to secure funding for a substantial programme of R&D, in the lead up to the beginning of telescope operations in 2022. Through this consortium, LSST:UK has secured data rights for 100 Affiliate PIs (plus the associated 400 Junior Associates), and embarked on an 8-year research and development programme that will yield a UK-based LSST Data Access Centre, tailored to the specific requirements of priority UK astronomy goals. In this talk, I will share highlights from the UK programme to date, including an alert-handling service that is being trialled on the Zwicky Transient Facility, large-scale database ingest and query experiments, toward the 35 billion objects that LSST is predicted to observe, and a fledgling cloud-based deployment of an analysis platform that will be at the heart of the UK DAC. I will also preview the plans for the next phase of work, during 2019--2023, which are likely to involve closer international collaboration on provisioning of data and associated analysis services as well as the finalisation of plans for UK-led User-generated Products, as we transition from the construction to the commissioning phase of LSST.

Martin Eriksen.pdf

The PAU Survey (PAUS) is an innovative photometric survey with 40 narrow bands at the William Herschel Telescope (WHT). The narrow bands are spaced at 100 ansgstron intervals covering the range 4500to 8500 angstron and, in combination with standard broad bands, enable excellent redshift precision. This talk discuss the technique, galaxy templates and additional photometric calibration used to determine early photometric redshifts from PAUS. Using BCNZ2, a new photometric redshift code developed for this purpose, we characterise the photometric redshift performance using PAUS data on the COSMOS field. Comparison to secure spectra from zCOSMOS DR3 shows that PAUS achieves σ68/(1+z) = 0.0037 to iAB < 22.5 when selecting the best 50% of the sources based on a photometric redshift quality cut. Furthermore, a higher photo-z precision (σ68 /(1+z) ~ 0.001) is obtained for a bright and high quality selection, which is driven by the identification of emission lines. We conclude that PAUS meets its design goals, opening up a hitherto uncharted regime of deep, wide, and dense galaxy survey with precise redshifts that will provide unique insights into the formation, evolution and clustering of galaxies, as well as their intrinsic alignments.

SciServer (www.sciserver.org) is an online system for scientific research and education with big data. The system offers access to several Petabyte-scale scientific datasets in fields ranging from astronomy to turbulence to genomics, along with a set of simple but powerful browser-based tools to visualize and analyze those datasets. The power of SciServer lies in its close connection to datasets like the Sloan Digital Sky Survey (SDSS), allowing for simple, fast analysis with minimal setup. The SciServer Dashboard offers quick access to all SciServer tools and datasets, and to all prior work within the system. All users up to 10 GB of file and database storage space – and through the Dashboard, users can manage uploaded data files, and can create collaborative groups to share datasets and scripts publicly or with selected colleagues. SciServer makes it easy to share exactly the right data with exactly the right people. SciServer’s Compute tool enables online computational analysis of big data through Jupyter notebooks. With only a few clicks, a user can create a customized environment on fast, high-memory virtual machines hosted by IDIES, where they can write or upload Python, R, or Matlab scripts to perform all sorts of data-intensive tasks. Importantly, SciServer allows these scripts to be run in either interactive or batch mode, meaning that even the most demanding data-intensive analyses can be completed with ease. To help scale up research quickly, SciServer Compute features a wealth of “getting started” data files and example notebooks that can be adapted to meet researchers’ needs. In addition to SciServer’s obvious potential for data-intensive science and engineering research, the system has been used effectively in many educational settings, particularly as data-intensive lab activities for undergraduate science courses. Learners get immediate access to high-performance computing resources without the need to install and configure software. A new set of “SciServer Courseware” notebooks creates an environment to manage learning activities by creating shareable user volumes and groups so that students and TAs can access files with appropriate permissions. SciServer is funded by National Science Foundation award ACI-1261715. For more information, please visit www.sciserver.org or contact the SciServer Helpdesk at sciserver-helpdesk@jhu.edu

bechtol_2018.pdf

As the integrated Large Synoptic Survey Telescope (LSST) system comes together during commissioning, we need to understand the degree to which the camera, telescope, and data management system are functioning together in a way that will support the high-level scientific goals of the 10-year survey. Accordingly, a major goal of commissioning is to quantify the distribution of performance of the as-built LSST system using a combination of on-sky data, informed simulations, and external datasets. These studies can then be used to inform early operations. I will describe the systems engineering approach adopted by the LSST Project for verification, validation, and characterization, and discuss the current status and plans for sustained data-taking and analysis campaigns during commissioning.

Celso-Mendes.pdf

High-Performance Computing (HPC) is an area where numerous exciting advances have been observed recently. Besides their concrete economic impact to society in general, those advances have truly improved the rate of scientific discoveries. In fact, the use of high-performance machines for simulations has become prevalent in most developments in science and engineering today. In this talk, we will briefly describe the status of existing HPC systems, in Brazil and abroad, pointing to the technological factors that enabled this scenario, including Moore’s Law and multi-core processors. We will then present the major paradigms that are presently used to program these systems, and examples of large scientific applications that have been developed under some of these paradigms. Finally, we will close with a personal view of current trends and challenges that the HPC community will face in the near future, and potential directions for further progress.

Amanda_Bauer.pdf

The Large Synoptic Survey Telescope (LSST) will conduct a 10-year wide, fast, and deep survey of the night sky, and will have a unique EPO program that will go live when the telescope starts operating in late 2022. EPO will enable public access to a subset of LSST data so anyone can explore the universe and be part of the discovery process. In this talk I will describe some major components of the EPO program, including online notebooks that will enable educators to provide LSST data in their classrooms without needing to download and maintain software or data files, an interactive Skyviewer, original multimedia for informal science centers and planetariums, and citizen science projects that use LSST data.

Ranpal Gill.pdf

In this presentation we will explain the mission of the Communication Office and how this influences what we do. We will provide details and examples of the tasks we carry out, how we coordinate, collaborate and communicate with partners SLAC, NCSA & IN2P3 and with our community. Branding and what it means to use the LSST name and brand will also be covered. It is the intention that attendees will gain insight into how the Communications Office functions leading to potential future collaboration to benefit the community as a whole.

William_O'Mullane.pdf

In this talk a brief update on the status of LSST in general as well as DM specifically will be given. We shall go into some details on the structure and organisation of Data Management.

Victor Krabbendam .pdf

LSST started construction in 2014 after a decade of consideration, design and early development.There has been tremendous progress in the last 4 years to make the full LSST system a reality. This talk will review the challenging objectives of the LSST and the current progress and achievements across the Project. LSST remains on schedule to begin the wide, fast, deep optical survey of the visible sky starting in October 2022.

Marko.pdf

Abstract: I will briefly review the perturbation theory approach to clustering of matter and galaxies and show how well the theoretical predictions match the simulations. I will particularly focus on the so called IR resummation and predictions for the shape of the BAO peak. I will also discuss the limitations of perturbative calculations and how the theoretical uncertainties impact the inference of cosmological parameters in galaxy surveys. Finally, I will mention some of the open questions in analytical modelling of LSS and strategies to resolve them.

The Large Synoptic Survey Telescope (LSST) is the most ambitious all sky survey of the universe ever proposed. In just its first month of operation LSST will see more of the universe at optical wavelengths than all previous telescopes built by mankind. LSST will conduct a 10-year survey of the sky that will deliver a 200 petabyte set of images and data products that will address some of the most pressing questions about the structure and evolution of the universe and the objects within it: Dark Matter and Dark Energy, Hazardous Asteroids and the Remote Solar System, The Transient Optical Sky and The Formation and Structure of the Milky Way. The LSST Corporation (LSSTC) was formed to initiate the LSST Project and advance astronomy and physics. LSSTC represents nearly 40 US & Chilean institutional members, as well as 74 international institutions representing 23 countries and over 1500 scientists and researchers. LSSTC partners with NSF/AURA and DOE/SLAC in LSST operations and will enable the exploitation of LSST’s data by advocating for and supporting LSST science. I will talk about being part of LSST, LSSTC as an academic at an university in UK, a country that is neither a main funder or the host nation.

marcel_schmittfull.pdf

The lensing convergence measurable with future CMB experiments will be highly correlated with the clustering of galaxies that will be observed by imaging surveys such as LSST. I will discuss prospects for using that cross-correlation signal to constrain local primordial non-Gaussianity, the amplitude of matter fluctuations as a function of redshift, halo bias, and possibly the sum of neutrino masses. A key limitation for such analyses and large-scale structure analyses in general is that the mapping from initial conditions to observables is nonlinear for wavenumbers k>0.1h/Mpc. This can destroy cosmological information or move it to non-Gaussian tails of the probability distribution that are difficult to measure. I will describe how we can use recently developed initial condition reconstruction methods to help us recover some of that information in the nonlinear regime.

ezequiel_treister.pdf

In this informal talk I will give a brief overview of the LSST project and present an update of the status of its construction. I will then describe the Chilean participation on LSST and our involvement in the different scientific collaborations, with some focus on the AGN Science Collaboration, of which I am a member. Finally, I will present the current data rights and data access plan and how can it impact international contributors, leaving time for questions and comments.

seth_siegel.pdf

The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a new radio interferometer located at the Dominion Radio Astrophysical Observatory (DRAO) near Penticton, British Columbia. Every day CHIME maps the entire northern half of the sky at radio frequencies between 400-800 MHz with a synthesized beam resolution of 20-40 arcminutes. Over the next 5 years, CHIME will produce a three-dimensional intensity map of the 21 cm radiation from neutral hydrogen over a 600 cubic Gpc volume. This will enable a measurement of the scale of the Baryon Acoustic Oscillations (BAO) in both the angular and line-of-sight direction across the redshift range z=0.8-2.5. This in turn will provide precise constraints on the angular diameter distance and expansion rate during the epoch when dark energy generated the transition from decelerated to accelerated expansion of the Universe. CHIME began collecting science data in March 2018. In this talk I will lead you on a virtual tour of the experiment. I\\\\\\\'ll provide an update on its current status and a first look at the data that it has collected. The primary challenge facing CHIME is the removal of astrophysical foregrounds that are several orders of magnitudes brighter than the cosmological 21 cm signal of interest. Our ability to remove these foregrounds depends on characterizing the instrument at an unprecedented level. I\\\\\\\'ll discuss the calibration strategies that are being pursued to measure our antenna beam patterns and time varying receiver gains with the required precision. Assuming that we are able to meet the foreground challenge, I\\\\\\\'ll conclude with a forecast on the cosmological constraints that we expect to place.

rafael_santos.pdf

There has been a lot of hype around Data Science -- online academic and technical courses, videos, books, blogs, job opportunities, etc. It seems that Data Science is the dream job of the (very near) future, and there are huge opportunities and salaries for data scientists. In this talk I will present different views of what Data Science is and what is expected from a data scientist, trying to filter out the hype. While there is a need for professionals specialized in extracting knowledge from data, we will see that most of the knowledge required to be a data scientist is already being employed by researchers in areas like astronomy, bioinformatics, remote sensing, banking, etc.: in these cases Data Science is more useful as an organizational approach for data-based experiments. This is a non-technical talk, and is the first lecture in a graduate-level course on Data Science at INPE, the Brazilian National Institute for Space Research.

Katrin Heitmann.pdf

Cosmology -- the study of the origin, evolution, and constituents of the Universe -- is now entering one of its most scientifically exciting phases. Three decades of surveying the sky have culminated in the celebrated \"Cosmological Standard Model\". Yet, two of its key pillars, dark matter and dark energy -- together accounting for 95% of the mass-energy of the Universe -- remain mysterious. Next-generation observatories will open new routes to understand the true nature of the \"Dark Universe\". These observations will pose tremendous challenges on many fronts -- from the sheer size of the data that will be collected (more than a hundred Petabytes) to its modeling and interpretation. The interpretation of the data requires sophisticated simulations on the world\'s largest supercomputers. The cost of these simulations, the uncertainties in our modeling abilities, and the fact that we have only one Universe that we can observe opposed to carrying out controlled experiments, all come together to create a major test for our future data analysis capabilities. In this talk I will discuss an ambitious end-to-end simulation project that attempts to provide a faithful view of the Universe as seen through the Large Synoptic Survey Telescope (LSST). This simulation project is the foundation for the second data challenge (DC2) carried out by the LSST Dark Energy Science Collaboration (LSST DESC). I will briefly describe how these complex, large-scale simulations will be used in order to prepare the collaboration for the arrival of LSST data.

The LSST Science Platform is the set of interfaces that will be provided to the LSST data, user storage, and user computing. The presentation will cover the three “Aspects” of the Science Platform: the data access APIs, providing IVOA-standard and other interfaces to the LSST catalog and image data; the Portal Aspect, providing a Web interface for discovering, querying, and visualizing LSST data products and user data; and the Notebook Aspect, providing a JupyterLab environment for user-driven data access and analysis in Python. I will describe and demonstrate the features already present in the current prototypes and the capabilities still planned for future development.

Matias_Carrasco.pdf

Data Access is such a simple term to understand but can hide many layers of complex systems and ideas thus it can be unequivocally be interpreted and explained in many different ways in regards software, technology, abstraction or design. This is also true in the context of astronomical data, both literally and figuratively. In this talk I will discuss a personal view on what data access means for astronomical surveys and how we can improve it, on how scientific cloud computing is rapidly evolving and being adopted and on how the revolution current open source technologies like containers, Jupyter and micro services are changing the way we understand and do Astronomy.

andrew_connolly.pdf

Machine learning has become integral to the analysis of astronomical data over the last decade. It has aided in a number of ground breaking results; from the identification of early onset supernovae to the efficient selection of QSOs from large survey data sets. In this talk I will describe some of the developments in machine-learning applications that impacted astronomical discoveries, describe why some techniques that, at first, appeared superior to existing applications did not gain traction in the astronomical community, and look at emerging methodologies that may impact astronomical surveys such as the Large Synoptic Survey Telescope

Jennifer_Johnson.pdf

Reliable stellar ages hold the key to numerous questions of galaxy and stellar system formation. However, they have been frustratingly hard to measure for field stars. While Gaia will improve the situation markedly for nearby turnoff stars, determination of ages for giants will not benefit to the same degree. In this talk, I will discuss the calibration of chemical ages, based on [C/N], which tags the mass of the star, and [alpha/Fe], which tags the time since star formation began. I will use these ages to discuss outstanding problems in the Galaxy, including the amount of radial mixing through the disk, the prevalence of stellar mergers, and the inside-out formation of the Galaxy. I will also preview the Milky Way Mapper, part of SDSS-V that will provide an unprecedented view of the stellar populations of the Galaxy.

Scott_Anderson.pdf

The Black Hole Mapper is among the main science programs of the next generation Sloan Digital Sky Survey (SDSS-V), actively being developed for dual-hemisphere, wide-area, multi-epoch and multi-object spectroscopy (MOS), starting 2020. Black Hole Mapper (BHM) exploits two hallmark characteristics of accreting supermassive black holes (SMBHs) in quasars to assess their fundamental parameters, astrophysics, and evolution: optical spectral variability on a range of timescales from days to decades, and prodigious luminosities extending even up to X-ray energies. In the time-domain, tens of thousands of quasars will be (re)observed with MOS at a range of cadences, with the bulk having a few to a dozen epochs added in SDSS-V, e.g., suitable for exploring accretion astrophysics and transitions such as changing look quasars; and BHM time-domain efforts will more-intensively study >1000 quasars, each with hundreds of spectral epochs for reverberation measures of masses of SMBHs across a broad range of redshift and luminosity. BHM additionally will reveal the identifications and natures (redshift, spectral subclass etc.) of the optical counterparts to hundreds of thousands of X-ray sources (mainly AGN) discovered in initial years of the upcoming eROSITA surveys of the X-ray sky; the eROSITA/SDSS-V combination will yield an obscuration unbiased probe of SMBH demographics and evolution, again with orders of magnitude advances. [BHM optical IDs of eROSITA sources will also yield X-ray emitting clusters of galaxies, compact binaries and CVs, and active late-type stars]. An overview is provided of the status of BHM planning, as we continue to expand our international collaboration.

Niv_Drory.pdf

The LVM in SDSS-V will take the first step towards the “spectral panopticon”, a full spectroscopic image of the sky, providing optical IFU data-cubes to resolve, e.g., SF structures, GMCs, H II regions and young stellar clusters. The LVM will cover the bulk of the MW disk at 0.1-1 pc resolution, the Magellanic Clouds at 10 pc resolution, M31 & M33 at 20 pc resolution, and Local Volume galaxies out to a distance of 8 Mpc at ∼ 25-100 pc resolution, in total about 1 steradian of sky. LVM covers the full optical bandpass at R~4000. Optical spectroscopy specifically addresses two physical components of galaxies: the ionized ISM and stellar populations. The LVM sky coverage will overlap with datasets of stellar spectra from SDSS-III,IV and V, resolved photometry of individual stars and color-magnitude diagrams (CMDs) in the LMC, SMC (ground based), M31, and M33 (HST). In the MW, we complement the SDSS-III, IV, and V APOGEE spectroscopy of millions of stars by probing the ISM around them. Using the stellar types, ages and abundances from APOGEE we will be able to infer and probe the radiation field and wind momentum input of stars back into the ISM. Across all the Local Volume targets, LVM will overlap with far-IR, sub-mm, and radio datasets probing the cold phases of the ISM (dust, H2, and H I), connecting the onset and effects of SF to local ISM conditions. In the Magellanic Clouds and the MW, LVM will probe the ionization of gas around X-ray binaries (including a full census of X-ray sources in the LMC by the eROSITA satellite) opening a window to study the interaction of accretion onto stellar mass black holes and the surrounding ISM. The wide area covered by the LVM will sample a large variety of SF regions caught at different stages of their life cycles, as probed by the age estimated from resolved stellar data (stellar spectroscopy and CMDs).

Juna_Kollmeier.pdf

I will describe the current plans for the Fifth Generation of SDSS. SDSS-V will be an unprecedented all-sky spectroscopic survey of over six million objects. It is designed to decode the history of the Milky Way galaxy, trace the emergence of the chemical elements, reveal the inner workings of stars, and investigate the origin of planets. It will provide the most comprehensive all-sky spectroscopy to multiply the science from the Gaia, TESS and eROSITA missions. SDSS will also create a contiguous spectroscopic map of the interstellar gas in the Milky Way and nearby galaxies that is 1,000 times larger than the state of the art, uncovering the self-regulation mechanisms of galactic ecosystems. It will pioneer systematic, spectroscopic monitoring across the whole sky, revealing changes on timescales from 20 minutes to 20 years. The project is now developing new hardware to build on the SDSS-IV infrastructure, designing the detailed survey strategy, and actively seeking to complete its consortium of institutional and individual members.

David_Alonso.pdf

I will describe the potential of LSST to constrain dark energy and other cosmological phenomena. In particular I will focus on the work currently being done within the collaboration to prepare ourselves to analyze the data after 2021. I will focus on a few projects I have been involved in: the development of the Core Cosmology Library, the construction of an end-to-end analysis pipeline for large-scale structure data, the recent 3x2pt pipeline project, and the development of TJPCosmo, a general and robust joint-probes likelihood module for the analysis of the 5 DESC probes.

Niel_Brandt.pdf

The LSST will enable studies of the growing supermassive black holes (SMBHs) in active galactic nuclei (AGNs) on a truly massive scale. After a brief review of the LSST surveys from an AGN perspective, I will describe the selection of tens of millions of AGNs using LSST plus multiwavelength data. I will then highlight three examples of exciting LSST AGN science investigations: massive AGN variability studies, transient SMBH fueling events, and high-redshift AGNs. I will end by describing the details of the LSST AGN Science Collaboration, its ongoing activities, and its future plans.

Dominique_Boutigny.pdf

Together with NCSA, the IN2P3 Computing Center (CC-IN2P3) in France will be processing 50% of the LSST data to produce the annual Data Releases. Both computing centers will then exchange their respective data sets to constitute a complete data archive at both sites. In parallel, IN2P3 is also planning to deploy an LSST Data Access Center with analysis capabilities, targeting the science community. These projects contains several technical challenges that I will describe in details. I will also expose the strategy that we have put in place in order to check that the designed technical solutions are actually matching the scientific needs.

Melissa_Graham.pdf

The LSST will begin preliminary commissioning next year, and is projected to start its 10-year survey of the southern sky in 2022. I will provide a brief overview of the main science drivers and survey design, and give a status update of the project with a focus on the LSST\\\'s Data Management system: the data processing pipelines, the products they generate (images, catalogs, and alerts), the planned user interface for scientific queries and analysis, and the data access timescales and policies that are relevant to Brazilian astronomers. I will also cover the current activities of the LSST Science Collaborations, which are actively engaging the community to prepare for LSST, and their existing channels for communication and participation. Finally, I will outline the open opportunities for future users to help LSST refine its observational strategies for the main survey (wide-fast-deep), mini-surveys, and deep drilling fields.

Francisco_Javier.pdf

With the advent of the next generation galaxy surveys, a need for higher precision modeling and systematics control arises. End-to-end simulations are a great tool to achieve these goals. Though more traditional in particle physics, in the recent years there has been an effort from the astronomical/cosmological community to generate high-fidelity simulated astronomical images. The Dark Energy Science Collaboration (DESC) is now involved in the so-called Data Challenge 2 (DC2), which constitutes a collaboration-wide effort to generate synthetic mocks and simulated images to perform end-to-end analyses. I will give a detailed overview of this data challenge: what it is, what the goals are and how DESC collaborators can get involved.

Andreas_Wicenec.pdf

In this presentation I will try to bridge historic efforts of humankind to gather and use knowledge and understanding of astronomical phenomena to the modern era of collecting and analysing exponentially growing amounts of digital data while keeping the number of scientists almost constant. I will describe the challenges posed by this obvious bottleneck and also present work we are undertaking in tackling them in order to enable scientists to efficiently extract knowledge.

Kyle_Chard.pdf

Scientists are increasingly reliant on the analysis of large datasets and use of parallel computing resources. While scientific workflows have long been used to simplify the construction of parallel applications, few systems are well equipped to handle new forms of analysis such as those presented by machine learning and data analytics, interactive analysis in Jupyter notebooks, and online computing. The task of developing and executing a variety of analyses at scale can be difficult, requiring complex orchestration and management of applications, data staging across wide area networks, and customization for specific execution environments. In this talk we introduce Parsl (Parallel Scripting Library), a pure Python library for orchestrating the concurrent execution of multiple tasks that is designed to meet the needs of new analysis modalities. Parsl is remarkable for its simplicity. Developers simply annotate functions (either pure Python or wrappers around shell programs) and write application logic to link these functions in Python. Calls to these annotated functions then result in the creation of “tasks” that run concurrently with the main program and other tasks, subject to dataflow constraints defined by the availability of input data. Parsl abstracts hardware details, allowing the same script to be executed efficiently on one or more laptops, clusters, clouds, and/or supercomputers.

Dante_Minniti.pdf

The ESO Public Survey VISTA Variables in the Via Lactea (VVV) has been mapping the Milky Way bulge and the Southern mid-plane in the near-IR since 2010. An extension of this survey started to map the gaps left between the coverage of the VISTA Hemisphere Survey and the VVV Survey. This VVV eXtended Survey (VVVX) would take about 200 nights in total, covering 2x10^9 point sources within an area of about 1700 sq deg. The area survey includes about 50 known globular clusters, and >1000 known open clusters, with many more clusters to be found. The final products will be deep JHKs-band images, and catalogues of variable point sources, and of proper motions. The main aims are to study the different stellar populations present in the inner Galaxy, and to produce a 3-D map of the surveyed region using well-known distance indicators (such as RR Lyrae, Cepheids, and red clump giants). In order to do all this, it is critical to do a variability search, and to have a good understanding of the effects of reddening and extinction in the near-IR. Within the existing bulge VVV area proper motions would also be available. In particular, the VVVX results will be an essential complement to forthcoming near-IR multiplexing spectrographs (MOONS, APOGEE-S). In addition, the VVVX survey results will complement the expected measurements from important space missions (GAIA, WFIRST).

Knut_Olsen.pdf

LSST will be revolutionary for Milky Way and Local Volume science. I will discuss a few Milky Way-related science cases that will benefit from LSST measurements, with particular focus on science related to the Magellanic Clouds. I will also discuss some of the technical challenges that we need to overcome to maximize LSST’s output with respect to these science cases. Finally, I will indicate a number of ways in which the stellar populations scientific community is preparing for LSST, including organizing topical science workshops and using existing datasets to address some of the challenges. A key goal of the NOAO Data Lab is to give scientists a platform for experimenting with workflows applicable to the LSST era.

Hugo Camacho.pdf

BAO measurements has been proven to be a robust and precise method for measuring cosmological distances when using spectroscopic redshifts. In this webinar we will show how a similar level of robustness can be achieved using purely photometric data. We will present measurements of the BAO signal in galaxies selected from the first year of Dark Energy Survey data with an effective area of 1318 square degrees and photometric redshifts in the range [0.6, 1.0]. The results shown to be consistent with the flat Lambda-CDM concordance cosmological model supported by numerous other recent experimental results, robust to a number of stress tests and consistent with simulations of the DES Y1 dataset.

David_Rosario.pdf

The properties of cold molecular gas in galaxies are sensitive to the nature and efficiency of star-formation within molecular clouds. I will report on a carefully controlled CO spectroscopic study of a complete volume-limited set of the most luminous nearby (D < 40 Mpc) Seyfert galaxies, to understand whether their gas fractions and star-formation efficiencies are influenced by the presence of the AGN. We find no difference between AGN and inactive galaxies; indeed, the star-formation efficiencies in the centres of Seyferts are consistent with their larger-scale discs. Putting this in the context of relevant energies and timescales, we examine the resilience of star-forming molecular gas against the effects of AGN feedback.

Mark_Allen.pdf

The CDS is an astronomy data centre that develops services that are widely used by the international community: SIMBAD, the reference database for nomenclature and bibliography of astronomical objects (outside the solar system), VizieR, the service for astronomical catalogues and tables published in journals, the Aladin interactive sky atlas and VO portal, and the CDS X-Match large catalogue cross-correlation service. The content of the CDS is built with strong collaborative relationships with the astronomy journals, observatories, space agencies and projects. The CDS services are compliant with IVOA standards, and the CDS helps build the astronomy data e-Infrastructure via contributions to the definition of the standards. Recent advances in all-sky VO technologies have enabled new innovative ways of using astronomy data, one example being the CDS Aladin-Lite tool and the Hierarchical Progressive Surveys (HiPS) system for the sharing of large survey data. This system is being widely implemented such as in ESASky, JAXA, NOAO and many more, forming a HiPS network and being standardised at IVOA. It is also an integral part of the newly released CDS Portal. In this presentation I will highlight recent advances, the challenges, and future directions of the CDS.

Meg_Schwamb.pdf

The Large Synoptic Survey Telescope (LSST) is uniquely equipped to search for Solar System bodies due to its unprecedented combination of depth and wide field coverage. Starting in 2022, LSST will generate the largest catalog of Solar System objects to date. Over its 10-year lifespan, LSST is expected to catalog over 5 million Main Belt asteroids, almost 300,000 Jupiter Trojans, over 100,000 Near Earth Objects (NEOs), over 40,000 Kuiper belt objects (KBOs), tens of interstellar objects, and over 10,000 comets. Many of these objects will receive hundreds of observations in multiple bandpasses. LSST will report detections of moving objects in various filters (ugrizy) between approximately 16 and 24.5 magnitudes (in r band) over its observing footprint (covering ∼18,000 square degrees in the Wide-Fast-Deep survey), link these detections into orbits, and provide metadata on observing conditions. It will be up to the planetary community to apply a wide variety of methods to synthesize and combine this information in order to fully leverage the LSST dataset for Solar System science. I will present an overview of LSST\'s capabilities and describe the current and future efforts of the LSST Solar System Science Collaboration (SSSC) to prepare methods and tools to analyze this data, as well as understand optimum survey strategies for discovering moving objects throughout the Solar System.

Bradley_Peterson.pdf

The Large Ultraviolet, Optical, and Infrared Surveyor (LUVOIR) is one of the future-generation mission concepts identified in the NASA Astrophysics Roadmap of 2014. NASA is currently funding studies of four flagship-class missions with the intent of identifying the science goals and concomitant technical requirements to make sure that the mission concepts are sufficiently mature that they could be recommended as priorities by the 2020 NRC decadal survey. Each mission concept is being studied by a community-based Science and Technology Definition Team (STDT). The LUVOIR STDT is studying two telescope concepts, both using segmented mirrors that will autonomously deploy in space, like the James Webb Space Telescope (JWST). The notional designs are a 15.1-m aperture that will require the 8.4-m fairing of the Block 2 Space Launch System and a 9.2-m that can be launched in a 5-m fairing on a smaller, although still highly capable, launch vehicle. The LUVOIR STDT is studying imagers and spectrographs that cover the range 100 nm to 2.5 microns and have 100-1000 times the performance of the Hubble Space Telescope (HST). A coronagraph that will enable detection of Earth-like planets in the habitable zone of nearby stars is one the highest priorities and biggest challenges. LUVOIR is being designed to be serviceable, even though this will be a challenge from its orbit at Sun-Earth L2. Opportunities for international contributions will be sought. It is expected that the LUVOIR science program will be driven largely by guest observers, in the same manner as HST and JWST, and will be used for a wide variety of astronomical observations, from cosmology to exoplanets to our own Solar System.

Stephanie_Juneau.pdf

As we keep progressing into an era of increasingly large astronomy datasets, the NOAO Data Lab (datalab.noao.edu), is developing a suite of analysis tools to maximize potential for discoveries and extraction of scientific knowledge. The services are organized around large astronomy surveys – both in-house and external – and include databases, query managers, virtual storage space, workflows through our Jupyter Notebook server, or scripted analysis with the ‘datalab’ command. Working at the intersection of astronomy and data science, our main goal is to provide users with tools to work close to the data, and thus optimize the scientific productivity of the astronomy community. We currently host datasets from NOAO facilities such as the Dark Energy Survey (DES), the DESI imaging Legacy Surveys (LS), the Dark Energy Camera Plane Survey (DECaPS), and the nearly all-sky NOAO Source Catalog (NSC). We are further preparing for large spectroscopic datasets such as DESI. After an overview of the Data Lab and datasets, I will showcase scientific applications on topics such as star/galaxy separation, finding dwarf galaxies, and extragalactic large-scale structures. I will also present steps for new users to get started conducting their own analysis, and describe our vision for future developments as we tackle the next technical and scientific challenges.

Roberto_Martins.pdf

In our solar system, five bodies are currently classified as dwarf planets. Recent stellar occultation revealed a dense ring around the Trans-Neptunian dwarf planet Haumea. Exception made to the giant planets, this is the second body known to have a ring. The formation of stable rings around small bodies is difficult to explain and, in the case of Haumea, that has the shape of a very elongated ellipsoid and a fast rotation, it is even more surprising. I will show how the discovery was possible, the procedures used to obtain the physical data of Haumea, and what are the possible origins of the ring.

Antonella_Palmese.pdf

In the occasion of the exciting discovery of the electromagnetic counterpart of the GW170817 gravitational wave event, the Dark Energy Survey collaboration produced a series of studies covering different aspects of the event. In this talk, I will present the Dark Energy Survey gravitational wave follow up program and how observations of the GW170817 host galaxy can provide information about the formation of the binary neutron star that merged, producing the gravitational wave signal.

Marcel_Popescu.pdf

Alexandre_Refregier.pdf

Weak gravitational lensing is a unique technique to map the distribution of dark matter in the universe. It is also a sensitive probe of large scale structures in the universe and cosmological parameters. I will first briefly describe the principles of weak lensing. I will then review the current observational status of this field, highlighting several new measurements especially from the ongoing Dark Energy Survey (DES). I will then discuss the status of tensions between cosmological probes and results for a new integrated approach to combine them.

Rebecca_Bernstein.pdf

In the last four centuries, ground based telescopes have provided some of the key discoveries that have driven our understanding of both astronomy and fundamental physics. In the coming decade, a new generation of ground- and space-based observatories will come on line, providing unprecedented potential for new discoveries in all areas of astrophysics and cosmology, from exoplanets and life to the birth of the first stars and galaxies at the edge of the visible universe. In this talk, I will provide an overview of the design and status of the Giant Magellan Telescope (GMT), which is a 25.4m diameter, optical/infrared telescope that is being built in northern Chile by an international collaboration of research institutions. It will provide a factor of three gain in angular resolution and an order of magnitude increase in collecting area relative to the previous generation of 8m telescopes. I will focus on some of the unique capabilities the GMT will provide in the coming decades.

Marcelle_Soares.pdf

Motivated by the exciting prospect of new wealth of information arising from the first observations of gravitational and electromagnetic radiation from the same astrophysical phenomena, the Dark Energy Survey (DES) has performed a broad range follow-up program for LIGO/Virgo events using the Dark Energy Camera (DECam). In this talk, I present the discovery of the optical transient associated with the neutron star merger GW170817 using DECam and discuss its implications for the emerging field: multi-messenger cosmology with gravitational waves and optical data.

Johnny_Greco.pdf

Low-surface-brightness galaxies (LSBGs) are a significant component of the galaxy population, which provide a unique testing ground for theoretical predictions of galaxy and star formation, stellar feedback processes, and the distribution and nature of dark matter. However, their defining characteristic—central surface brightnesses that are fainter than the night sky—makes them difficult to detect and study, leading to their underrepresentation in previous optical surveys and biasing our view of the full galaxy population. I will present a new view of these elusive galaxies from the Hyper Suprime-Cam (HSC) Survey, a 300-night imaging survey using the 8.2-meter Subaru Telescope on Mauna Kea. After giving an overview of the HSC Survey, I will present our source-detection pipeline and initial catalog of LSBGs within the first ~200 deg^2 of the survey, which will grow to 1400 deg^2 upon survey completion. Our LSBG catalog will facilitate follow-up efforts (which we have already started) to study the physical properties and number densities of these galaxies as a function of environment. Pushing such studies to lower surface brightnesses will be necessary to form a more complete census of the galaxy population, which will ultimately provide one of the strongest tests of the standard LCDM framework.

Daniel_Gruen.pdf

The Dark Energy Survey has combined analyses of galaxy clustering and weak gravitational lensing two-point correlation functions in its first year (Y1) of observations. This combination of measurements provides information on the amplitude of density fluctuations (S8=0.794+0.029-0.027) and the dark energy equation of state (w=-0.80+0.20-0.22) that is competitive with Planck CMB data. I will review these results, with a focus on the technical advances on shape measurement and photometric redshifts that facilitated them. I will also show preliminary results from novel work, called density tomography, that studies overdense and underdense lines of sight separately. The latter constrains the joint 1pt-PDF of matter density and galaxy count, sensitive also to higher order moments and galaxy stochasticity. This provides additional information and, by comparing the full shape of the PDF to predictions, a non-parametric test of gravity.

Ting_Li.pdf

The census of Milky Way satellite galaxies provides crucial tests of both galaxy formation models and the broader Cold Dark Matter paradigm. Over two-dozens of new Milky Way satellite candidates have been discovered in the last two years, primarily in data from the Dark Energy Survey (DES). These discoveries double the number of known Milky Way satellite galaxies, leading a huge advance in solving the missing satellite problem. Furthermore, many of these newly discovered dwarf galaxies are excellent targets for providing constraints on WIMP dark matter cross section and MACHO dark matter abundance. In this talk, I will present the latest discoveries of the Milky Way satellite galaxies in DES and show some initial results from a spectroscopic campaign on these satellite candidates using 4-8 meter class telescopes in the southern hemisphere.

AlbertoMolino_Webinar_170921.pdf

In this talk, i would like to present the new accurate photometric redshifts for galaxies observed by the Cluster Lensing and Supernova survey with Hubble (CLASH). CLASH observed 25 massive galaxy cluster cores with the Hubble Space Telescope in 16 filters spanning 0.2 - 1.7 m. Photometry in such crowded fields is challenging. Compared to our previously released catalogs, we make several improvements to the photometry, including smaller aper- tures, ICL subtraction, PSF matching, and empirically measured uncertainties. We further improve the Bayesian Photometric Redshift (BPZ) estimates by adding a redder elliptical template and by inflating the photometric uncertainties of the brightest galaxies. The resulting photometric redshift accuracies are dz/(1+z) ∼ 0.8%, 1.0%, 1.5%, 2.0%, and 2.2% for galaxies with I-band F814W AB magnitudes < 18, 20, 22, 23, and 25, respectively. These results are consistent with our expectations. They improve on our previously reported accuracies by a factor of 3 at the bright end and 60% at the faint end. Our catalogs include 1295 spectroscopic redshifts, including 561 confirmed cluster members. We also provide stellar mass estimates. Finally, we include lensing magnification estimates of background galaxies based on our public lens models. The catalogs of all 25 CLASH clusters are available via MAST. The analysis techniques developed here will be useful in other surveys of crowded fields, including the Frontier Fields and surveys carried out with J-PAS and JWST.

Michel_Aguena.pdf

Galaxy cluster are the largest gravitationally bound structures in the Universe. Mapping the abundance and spacial distribution of clusters we can trace the underlying dark matter field, and extract cosmological information such the history of expansion of the Universe and the growth of perturbation. However, in order to use galaxy clusters as cosmological probe, we have to consider observational effects, i. e. the selection function and the relation between the dark matter halo mass and a proxy. In this webinar, I will present the main steps to construct a cluster cosmology pipeline developed during my PhD.

Julian_Bautista.pdf

Rachel_Mandelbaum.pdf

Hyper Suprime-Cam (HSC) is an imaging camera mounted at the Prime Focus of the Subaru 8.2-m telescope operated by the National Astronomical Observatory of Japan on the summit of Maunakea in Hawaii. A consortium of astronomers from Japan, Taiwan and Princeton University is carrying out a three-layer, 300-night, multiband survey from 2014-2019 with this instrument. In this talk, I will focus on the HSC survey Wide Layer, which will cover 1400 square degrees in five broad bands (grizy), to a 5 sigma point-source depth of r~26. We have covered 240 square degrees of the Wide Layer in all five bands, and the median seeing in the i band is 0.60 arcseconds. This powerful combination of depth and image quality makes the HSC survey unique compared to other ongoing imaging surveys. In this talk I will describe the HSC survey dataset and the completed and ongoing science analyses with the survey Wide layer, including galaxy studies, strong and weak gravitational lensing, but with an emphasis on weak lensing. I will demonstrate the level of systematics control, the potential for competitive cosmology constraints, some early results, and describe some lessons learned that will be of use for other ongoing and future lensing surveys.

Joe_deRose.pdf

Using measurements of the matter power spectrum and the geometry of the universe at the surface of last scattering from CMB experiments we can make precise predictions for the amplitude of matter fluctuations at low redshift. Current galaxy surveys will be able to test these predictions so long as cosmologists are able to overcome the complex systematics associated with measuring cosmology using galaxies. In this talk I will overview the current analysis that one such galaxy survey, the Dark Energy Survey (DES), is pursuing with their first year of data. In particular, I will highlight the role that cosmological simulations have played in the analysis both in developing algorithms and in testing systematics mitigation techniques. I will conclude by discussing future prospects and challenges that will face simulators for upcoming analyses.

Michael_Strauss.pdf

There are now over 200 quasars known with redshifts above 5.5. I will discuss the search for these highest-redshift objects with various wide-field surveys. In many ways, the physical properties of high-redshift quasars are remarkably similar to those at lower redshift, even as quasars become increasingly rare at early cosmic epochs. Remarkably, the properties of the quasar host galaxies can be studies using submm observations of the dust continuum and molecular lines in the interstellar medium of these objects, which demonstrates that these objects are often embedded in extreme starbursting galaxies. Dust obscuration is another theme in quasar studies; an appreciable fraction of the growth of black holes may be hidden at optical wavelengths by dust. I will describe searches for obscured quasars at high redshift and low, and studies of their demographics and physical properties.

Bruno_Sicardy.pdf

Stellar occultations occur when a planetary body passes in front of a star. The spatial resolution depends on acquisition rate, reaching kilometric levels. Those events permit, among others, the detection of tenuous atmospheres (nbar level) and the discovery of new ring systems. We have developed in the last decades new calculation tools and new technological devices (fast cameras) in order to use stellar occultations for exploring the Solar Sytem beyond Neptune. Some highlights will be presented, in particular, the monitoring of Pluto\\\'s atmosphere and the surprising discovery of rings around an asteroid-like object, Chariklo. Up to now, the main limitation of the method has been the prediction accuracy, typically 40 milliarcsec (mas) projected on the sky, corresponding to some 500 to 1,500 km projected on Earth, depending on the body. This lead to large time dedicated to astrometry, tedious logistical issues, and more often than not, mere miss of the event. The Gaia catalog, with sub-mas accuracy, hugely improves both the star positions and ephemerides of the bodies, resulting in accuracies of ~10 km for the shadow track on Earth. Thus campaigns will be much more carefully planned, with success rate approaching 100%, weather permitting. Scientific perspectives will be presented, e.g. central flashes caused by Pluto’s or Triton\\\'s atmosphere may reveal hazes and winds near the surface, grazing occultations will show topographic features on remote bodies, allowing geological studies, occultations by Chariklo’s rings will unveil dynamical features such as resonances with nearby satellites or proper mode “breathing”. New atmospheres and rings will probably be discovered.

Antonino_Troja.pdf

Polyspectra represent one of the strongest tool in cosmology in order to derive information. The lowest order polyspectra, bispectrum and trispectrum, corresponding to the Fourier transform of the three- and four-points correlation function respectively, have been used in the past decades to derive information about the primordial physics of the Universe, as well as improving the results of the power spectrum only analysis. When we deal with spherical field, such as the Cosmic Microwave Background radiation (CMB), the Fourier transform is replaced by the Harmonic decomposition, performed using the Spherical Harmonics, i.e. the orthonormal basis of all the functions defined on the sphere, and the angular polyspectra are developed from the harmonic coefficients. Many models and estimators of angular polyspectra were developed, but there is still room for new ones. I will discuss of the spherical mathematical framework as well as the derivation and results of angular bispectrum of the Large Scale Structure (LSS) and the Needlet trispectrum of the CMB. The former case represent one of the first attempt made in order to constrain cosmological parameters using the bispectrum of the galaxy projected field along the line of sight. In the latter case, I\\\'ll show a new basis-like wavelet system in order to construct a strong estimator when the spherical field presents masked region, the Needlet system, with which it is possible to build a new estimator for the trispectrum.

Dominika Wylezalek.pdf

While many compelling models of AGN feedback exist, there is no clear data-driven picture of how winds are launched, how they propagate through the galaxy and what impact they have on the galactic gas. Recent work suggests that AGN luminosity plays an important role. In my talk, I will present results from several projects that focus on understanding the power, reach and impact of feedback processes exerted by AGN of different power. I will first describe recent efforts in our group of relating feedback signatures in powerful quasars to the specific star formation rate in their host galaxies, where our results are consistent with the AGN having a `negative\' impact through feedback on the galaxies\' star formation history. Feedback signatures seem to be best observable in gas-rich galaxies where the coupling of the AGN-driven wind to the gas is strongest, in agreement with recent simulations. But how and where does this quenching happen? Is it accomplished through the mechanical action of jets or through nuclear winds driven by radiation pressure? In the second part of my presentation, I will show that AGN signatures and AGN-driven winds can be easily hidden and not be apparent in the integrated spectrum of a galaxy hosting a low/intermediate-luminosity AGN. Using data from the new SDSS-IV MaNGA survey, we have developed a new AGN selection algorithm tailored to IFU data and we are uncovering a much more nuanced picture of AGN activity allowing us to discover AGN signatures at large distances from the galaxy center. This implies that large IFU surveys, such as the SDSS-IV MaNGA survey, might uncover many previously unknown AGN and feedback signatures related to them. Outflows and feedback from low- and intermediate-luminosity AGN might have been underestimated in the past but can potentially significantly contribute to the AGN/host-galaxy self-regulation.

Helena_Dominguez-Sanchez.pdf

Three billion years after the big bang (at redshift z = 2), half of the most massive galaxies were already old, quiescent systems with little to no residual star formation. How were the lives of these galaxies so they died so fast? In this talk, I will present recent results on the Star Formation Histories (SFHs) of a sample of ~ 100 quiescent massive (log M > 10 solar masses) galaxies at z=1.0 - 1.5, inferred from the analysis of spectro-photometric data from the SHARDS and HST/WFC3 G102-G141 surveys of the GOODS-N field. The data are compared to stellar population models assuming different SFHs, with the goal of determining 4 basic physical properties of red quiescent galaxies at high-z: their age, star formation timescale (tau), metallicity, and extinction. Thanks to the spectral resolution of the SHARDS plus G102 and G141 data, we are able to measure spectral features related to the age of the galaxies (MgUV and D4000), which allow us to break the typical age-tau, age extinction degeneracies with great confidence. We find that the derived SFHs for our MQGs are consistent with the slope and the location of the Main Sequence of star-forming galaxies (MS) at z > 1.2, when these galaxies were 0.5--1.0~Gyr old. According to the derived SFH, all of the MQGs experienced a Luminous Infrared Galaxy (LIRG) phase during typically ~500~Myr and roughly half of them went through ULIRG phase for ~100 Myr. I will also briefly introduce other projects I am involved in, including stellar population gradients of local ETGs with the MANGA survey and morphological classification of galaxies using Deep Learning.

Eric_Huff.pdf

Weak gravitational lensing is one of the most challenging cosmological measurements, and the difficulty of its extraction is driving much of the design of the big cosmological surveys. Significant progress has been made in the last few years, however, and it is likely that the coming generation of large imaging surveys will be limited only by sample size, and not by systematic measurement errors. As a result, it is now useful to think about new sources of lensing signal that are not accessible to WFIRST or LSST. I will talk about current challenges, and explain why I think the lensing shear calibration problem is now (mostly) solved. I will then describe how wide-field galaxy kinematics may open a promising new avenue for cosmological measurement, and discuss one possible way of obtaining them at the necessary scale.

Peter_Nugent.pptx

Astrophysics is transforming from a data-starved to a data-swamped discipline, fundamentally changing the nature of scientific inquiry and discovery. New technologies are enabling the detection, transmission, and storage of data of hitherto unimaginable quantity and quality across the electromagnetic, gravity and particle spectra. The observational data obtained during this decade alone will supersede everything accumulated over the preceding four thousand years of astronomy. Currently there are 4 large-scale photometric and spectroscopic surveys underway, each generating and/or utilizing hundreds of terabytes of data per year. Some will focus on the static universe while others will greatly expand our knowledge of transient phenomena. Maximizing the science from these programs requires integrating the processing pipeline with high-performance computing resources. These are coupled to large astrophysics databases while making use of machine learning algorithms with near real-time turnaround. Here I will present an overview of one of these programs, the Palomar Transient Factory (PTF). I will cover the processing and discovery pipeline we developed at LBNL and NERSC for it, several of the great discoveries made during the 7 years of observations, and where we are headed with a new facility, Zwicky Transient Facility starting August 2017, which will be an order of magnitude faster.

Ravi_Sheth.pdf

The Baryon Acoustic Peak oscillations imprint a characteristic length scale on the galaxy 2-point correlation function. This scale is related to, but distinct from, the local maximum of the correlation function on ~100 Mpc/h scales. In contrast to the local maximum, this scale is not affected by nonlinear effects to sub-percent precision. I will discuss how to estimate this scale, and the result of applying this analysis to the LOWZ and CMASS samples from the Twelfth Data Release (DR12) of the Baryon Oscillation Spectroscopic Survey (BOSS) collaboration.

Roberto_dePropris.pdf

The Milky Way is the quintessential example of a spiral galaxy and the only one whose stellar populations can be studied in detail. In particular, the bulge is the only resolved elliptical-like stellar system that we can observe, despite the extremely high foreground extinction and crowding. It has long been known that our Galaxy is a barred spiral and that our bulge belongs to the class of boxy/peanut shaped pseudobulges. We have completed the first radial velocity survey of the Southern bulge, using a total of nearly 10,000 M giants as tracers. Our study clearly shows that the entirety of the Galactic bulge is consistent with the stellar bar and no spheroidal component. We also present the first results of a new survey to probe the inner and oldest regions of the galaxy with RR Lyrae.

fabien_lacasa.pdf

Current and future galaxy surveys are reaching a high signal-to-noise regime, with the detection of clusters down to low masses and the measurement of galaxy clustering and weak lensing down to small scales. In this very regime, super-sample covariance (SSC) becomes the dominant source of statistical errors, for the Large Scale Structure observables that we use to improve our cosmological understanding of the universe. I will start with a pedagogical introduction of SSC in the case of cluster counts, where the effect is usually called sample (co)variance, before examining the precision of several analytical approximations designed in the flat sky limit. Then I will present how to predict SSC for an arbitrary survey geometry, as required by surveys such as DES, LSST or Euclid with a wide coverage far from the flat sky limit. I will show that SSC is poorly estimated with classical internal covariance methods relying on the data itself, such as bootstrap or jackknife. It is also poorly estimated from subsampling a given simulation, unless said simulation is considerably larger than the survey. The latter being a challenge for future surveys covering a large portion of the observable universe such as Euclid or LSST. Beyond cluster counts, SSC also affects galaxy clustering and weak-lensing and couples observables together, thus being a particular challenge for probe combination. I will briefly explore the link between SSC and recent advances on the theoretical (soft limits and consistency relations) and simulation (separate universes) fronts, before making the case for analytical prediction of SSC as the way forward for analysis of large surveys.

Bruno_Merin.pdf

ESASky is a science-driven discovery portal for all ESA space astronomy missions. The first public release of ESASky features interfaces for sky exploration and for single and multiple targets searches. Using the application requires no prior-knowledge of any of the missions involved and gives users world-wide simplified access to high-level science-ready public data products from space-based Astronomy missions, plus a number of ESA-produced source catalogues. HST data, metadata and products were some of the first to be accessible through ESASky. I will highlight the latest feature that we have developed, which allows the user to project onto the sky the footprints of the JWST instruments, at any chosen position and orientation. This tool has been developed to aid JWST astronomers when they are defining observing proposals. We aim to include other missions and instruments and to expand ESASky\\\'s functionalities in the future. I will demo the tool and ask for feedback on how to make it more useful.

deelman_linea.pdf

Scientific workflows allow researchers to declaratively describe potentially complex applications that are composed of individual computational components. Workflows also include a description of the data and control dependencies between the components. This talk will describe example workflows in various science domains including astronomy, bioinformatics, earthquake science, gravitational-wave physics, and others. It will examine the challenges faced by workflow management systems when executing complex workflows in distributed and high-performance computing environments. In particular the talk will describe the Pegasus Workflow Management System developed at USC/ISI (http://pegasus.isi.edu). Pegasus bridges the scientific domain and the execution environment by automatically mapping high-level workflow descriptions onto distributed resources. As part of this process, Pegasus may transform the workflow based on the workflow properties and the target architecture. The talk will describe the optimizations and techniques developed and used within the Pegasus system to efficiently manage data and computations across heterogeneous computing environments. Pegasus can execute workflows on a laptop, a campus cluster, grids, and clouds. It can handle workflows with a single task or millions of tasks and has been used to manage workflows accessing and generating Terabytes of data. The talk will also look at the challenges and opportunities that upcoming computing systems bring to workflow management systems.

RossanaRuggeri_talk.pdf

Forthcoming galaxy redshift surveys are motivated, to a large extent, by obtaining galaxy clustering measurements to accurately quantify the observed acceleration in the expansion of the Universe. It is to be hoped that these observations will reveal insight into the physical mechanism responsible for the cosmic acceleration, be it a new scalar field currently contributing to the energy budget of the Universe as Dark Energy, modification of gravitational laws on cosmological scales, or an unknown alternative to the Standard Cosmological Model. The statistical precision afforded by forthcoming surveys including DESI and Euclid is impressive and will push at least an order of magnitude beyond current measurements. However this promised low statistical errors will only be realised with the development of new, fast, analysis methods that reduce potential systematic problems to low levels. We present an efficient method for measuring the evolution of the growth of structure using Redshift Space Distortions (RSD), that removes the need to make measurements in redshift shells. We provide sets of galaxy-weights that cover a wide range in redshift, but are optimised to provide differential information about cosmological evolution. These are derived to optimally measure the coefficients of a parameterisation of the redshift-dependent matter density, which provides a framework to measure deviations from the concordance LCDM cosmology, allowing for deviations in both geometric and/or growth. We test the robustness of the weights by comparing with alternative schemes and investigate the impact of galaxy bias.

Tanga-Gaia_SSO_webinar_red.pdf

The ESA Gaia mission is performing since summer 2014 an all-sky survey of all sources brighter than V~20. Most of them are stars (more than one billion), but many Solar System object are also present: 350,000 asteroids, some TNOs, comets and planetary satellites. The main science driver of Gaia is provided by the unprecedented astrometric accuracy and the physical characterization by spectro-photometry for all sources. For the Solar System, these data represent the richest homogeneous survey available, providing access to an incredible variety of properties and potentially leading to major breakthroughs in asteroid science. Also, Gaia stellar astrometry in general is going to heavily impact ground-based observations, as a completely new calibration of the sky is accessible. Some simple exploitations of the first intermediate data release published in September 2016, already show the improvements brought to ground-based astrometry of asteroids, and demonstrate the completely renewed role of stellar occultations, an impressive tool of exploration whose efficiency is being multiplied by a large factor.

Data management in astronomy has undergone a series of radical transformations in living memory. While much of that has been because of the evolution of computing itself, the demands of astronomical processing have sometimes led ahead and sometimes lagged behind the capabilities of commodity IT. This talk is a personal view on how current developments in cloud computing are affecting the landscape of data processing and data publication, and what we can learn about past experiences to best take advantage of new trends in platforms and software engineering. I’m also going to share some practical lessons learned drawn from engaging with the commodity computing landscape within LSST’s Science Quality and Reliability Engineering (SQuaRE) team.

Brandt-LSST-Brazil-01.pdf

Data from the Large Synoptic Survey Telescope (LSST) will enable multiple breakthrough investigations of active galactic nuclei (AGNs) as well as typically dormant supermassive black holes (SMBHs). I will describe how the decade-long LSST main survey will discover at least 20 million AGNs across 18,000 deg^2, obtaining 60-180 visits per source for each of the ugrizy filters. Several extragalactic LSST Deep-Drilling Fields will provide even deeper coverage and denser temporal sampling for about a hundred thousand AGNs. Efficient AGN identification from z = 0-7.5 will be possible via a combination of techniques: color selection, variability selection, lack of proper motion, differential chromatic refraction patterns, and multiwavelength matching. I will also describe a few of the prime SMBH science investigations that LSST will enable including (1) massive investigations of AGN variability, (2) studies of transient SMBH fueling events, and (3) the identification of large AGN samples at high redshifts.

LSST-DataAccessServices-Brazil-Webinar-Final.pdf

The LSST will deliver two primary classes of data products: the near-real time stream of alerts to changes in the sky (so called \\\"Level 1” products), and the annual, systematics limited, reprocessing of the entire data sets (so called “Level 2” products, the \\\"Data Releases”). The scale of both of these products, but especially Level 2 (~few petabytes), will stress the ability of the users to download and analyze on their laptop. The LSST is therefore building a system to make it possible to perform some of the visualization and data analysis remotely. This environment, currently envisioned to be based on well known tools such as JupyterHub, will enable users to engage in interactive analysis (or run their analysis codes) at the LSST data center. Through it, the users will have access to fast database space, file storage, as well as a medium-scale computing cluster. In this talk, I will discuss our plans for such an environment -- a “data space” in which research with LSST data could be performed, and added value (“Level 3”) data products created.

Reports_SSSI.pdf

In this talk, I will summarize the results of two different efforts to determine how the US can best leverage the large upcoming surveys from DESI and LSST: the National Science Foundation-requested Kavli/NOAO/LSST report and the US Department of Energy-requested Cosmic Visions report. I will attempt to lay out the landscape of what observational resources may be available in the next decade and beyond. I will particularly focus on a project at the intersection of these two reports, a Southern Spectroscopic Survey Instrument (SSSI).

Nesta apresentação a motivação, filosofia, organização e objetivos para a formação do BPG-LSST serão discutidos. Alguns aspectos sobre o projeto LSST e o acordo que permitiu a participação deste grupo no LSST também serão apresentados. Finalmente, a importância de que o trabalho do BPG seja coordenado será enfatizada. Ao final da apresentação perguntas e comentários são bem vindos.

Mahabal_BrazilLSST_20161117.pdf

We will describe activity taking place as part of the year-long Program on Statistical, Mathematical and Computational Methods for Astronomy (ASTRO) at the Statistical and Applied Mathematical Sciences Institute (SAMSI). ASTRO hosts five working groups covering several topics in astrostatistics relevant to LSST science. We will provide an overview of activity in WG2 (Synoptic Time Domain Surveys), WG3 (Multivariate and Irregularly Sampled Time Series), and WG4 (Astrophysical Populations). WG2 has a number of subgroups covering setting up a data challenge, light-curve decomposition, incorporating ancillary information, outlier detection etc.. WG3 is covering time series topics arising in gravitational wave, exoplanet, and synoptic survey astronomy. WG4 is so far focusing on population studies for exoplanets, but is also covering science and methods relevant to LSST. An interesting area of overlap between WG3 and WG4 is the statistical area of functional data analysis (FDA): how to do statistics with populations of functions, rather than of scalars or small, fixed-length vectors (as in luminosity function estimation). Working Groups mostly meet remotely; some subgroups will become active only after the New Year, providing opportunities for new participants to join in some areas. Ashish Mahabal (Caltech) and Tom Loredo (Cornell University)

ISSC-SAMSI-ASTRO-Loredo+Mahabal-2016-11-17.pdf

We will describe activity taking place as part of the year-long Program on Statistical, Mathematical and Computational Methods for Astronomy (ASTRO) at the Statistical and Applied Mathematical Sciences Institute (SAMSI). ASTRO hosts five working groups covering several topics in astrostatistics relevant to LSST science. We will provide an overview of activity in WG2 (Synoptic Time Domain Surveys), WG3 (Multivariate and Irregularly Sampled Time Series), and WG4 (Astrophysical Populations). WG2 has a number of subgroups covering setting up a data challenge, light-curve decomposition, incorporating ancillary information, outlier detection etc.. WG3 is covering time series topics arising in gravitational wave, exoplanet, and synoptic survey astronomy. WG4 is so far focusing on population studies for exoplanets, but is also covering science and methods relevant to LSST. An interesting area of overlap between WG3 and WG4 is the statistical area of functional data analysis (FDA): how to do statistics with populations of functions, rather than of scalars or small, fixed-length vectors (as in luminosity function estimation). Working Groups mostly meet remotely; some subgroups will become active only after the New Year, providing opportunities for new participants to join in some areas. Ashish Mahabal (Caltech) and Tom Loredo (Cornell University)

wkl-RioWebinar-20161027.pdf

The Kilo-Degree Survey (KiDS) is mapping 1500 square degrees of sky using the ESO VLT Survey Telescope, a wide-field imaging telescope on Paranal. I will discuss the recent results presented in Hildebrandt et al (2016, 1606.05338) from a tomographic analysis of the matter power spectrum using weak gravitational lensing, as well as the implications of the measurements for cosmology.

Federica_Bianco.pdf

I will review the many scientific topics on transient and variable sky in which members of our collaboration are world-leading experts, from geometric transits to nuclear explosions, and give a brief overview of the expected and wished for results LSST could provide, and of the work needed to do to assure LSST\\\\\\\'s potential to explore the transient sky is unleashed.

One of the central questions of Galactic astrophysics is how galaxies form and evolve. The galaxy we can study in detail like no other is our own Milky Way. To this end, a number of ground-based spectroscopic and photometric Galactic surveys have been planned or currently ongoing. The Gaia DR1 is already complementing some of these (RAVE, APOGEE) with accurate proper motions and parallaxes. I will present recent observational results from the near-infrared spectroscopic survey APOGEE, which I will interpret using a chemo-dynamical model tailored to the Milky Way. I will argue that to break degeneracy among different Galactic evolution scenarios we need accurate stellar ages, such as those obtained through asteroseismology by the CoRoT and Kepler missions.

LSST_SciCollabs_overview.pdf

The LSST Science Collaborations are topical working groups of international scientists, who work together to provide scientifically-motivated feedback to survey implementation, develop software and data products to enable LSST science, and organize follow-up and analysis resources in preparation for LSST\'s first light. In this talk, I will discuss the structure of the science collaborations, their current activities, and how new LSST members can join the thriving collaboration community.

2016_huertas-company_webinar.pdf

The life of a galaxy is a balance between processes that trigger star formation by accelerating gas cooling and others which tend to prevent stars to form by expelling or heating gas. Over the past years, the picture is emerging that, during most of its life, a galaxy seems to live a rather quiet life, gradually growing in stellar mass through the formation of new stars which are formed at a rate remarkably proportional to its stellar mass, This is interpreted as an indirect evidence that fuel in the form of cold gas is somehow continuously being fed into the galaxies to sustain star formation. Two major events, eventually related, can break this apparent equilibrium. An episode of high star formation activity (e.g starburst) can be triggered. Or, suddenly something might happen that prevents the galaxy to continue forming new stars. Quenching is probably the most important event that a galaxy experiences during its life and a fundamental mechanism that helps understanding most of the properties of our surrounding Universe. There are a variety of different mechanisms entertained for the quenching process, e.g. feedback, interactions, halo driven shock heating, morphological quenching etc. Which one is dominantly driving galaxy evolution (if there is) or under which circumstances one or another process is triggered is still a mystery. In my talk I will focus on the relation between structure and quenching in massive galaxies. By using advanced machine intelligence techniques, I will analyze the relation between quenching and bulge growth in massive galaxies from z~3. I will in fact show evidences of two distinct channels for the growth of bulges in the massive end of the present day Hubble sequence (Huertas-Company+15ab).

HMcode - LIneA.pdf

Cosmological weak gravitational lensings surveys use the correlated distortions of galaxy shapes to infer properties of the matter distribution in the Universe. In principle, these measurements may then be used to constrain theories of the accelerated expansion, to infer the neutrino mass, and to learn about baryonic feedback processes. However, the interpretation of weak lensing data is complicated by the fact that non-linear structure along the line-of-sight contributes to the lensing signal. In this talk I will discuss how to model the non-linear matter distribution using N-body simulations and analytical techniques.

2016_webinar_YuanyuanZhang.pdf

Galaxy clusters are important subjects of study for both cosmology and astrophysics research. Ongoing optical surveys like the Dark Energy Survey (DES) are observing tens of thousands of clusters to redshift 1.0 and beyond. The evolution of cluster central galaxies is one topic that will benefit from the statistical power of DES data. The LambdaCDM model provides the big picture explanation for the formation of cluster galaxies. However, astrophysical processes like in situ star formation, stripping and disruption are critical in shaping the galaxies’ properties. In this webinar, I will present studies about cluster central galaxies with DES data. I will also discuss the high redshift prospect of the topic, utilizing the discovery power of DES on z > 1.0 clusters.