Webinars 326

Since 2011 we promote webinars which are an important aspect of our personnel development. This allows collaborators anywhere in the world to join seminars about the latest developments in several astronomical and technical fields. Webinars are presented in english and announced to a mailing list. Click here if you want to subscribe.

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Speakers 296

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Scheduled webinars 10

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22/04 - 11:00 am BRT

Allan Alves & Denise Köche ( Agência Propósito )

O que pensa e o que busca a comunidade científica na chegada do LSST

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.

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29/04 - 02:00 pm BRT

Samuel Schmidt ( University of California Davis )

Rubin Obs. Dark Energy Science Collaboration Photometric Redshifts: Challenges and Opportunities\"

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.

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06/05 - 03:00 pm BRT

Michael Blanton ( University of New York )


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13/05 - 11:00 am BRT

Francesco Valentino ( University of Copenhagen )

The life and death of massive galaxies

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20/05 - 11:00 am BRT

Thaisa Storchi-Bergmann ( Universidade Federal do Rio Grande do Sul )


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27/05 - 11:00 am BRT

Willian Vieira de Abreu ( Universidade Federal do Rio de Janeiro )

Divulgação científica na astronomia: experiências e perspectivas

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03/06 - 11:00 am BRT

( LIneA )


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10/06 - 12:00 am BRT

Robert Nikutta ( NOIRLab / Astro Data Lab )


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17/06 - 11:00 am BRT

Jacques Lépine ( Universidade de São Paulo )

The role of the co-rotation resonance in the Galactic disk and its influence on the Sun and stars of the Solar neighborhood

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01/07 - 11:00 am BRT

Wagner Corradi ( Universidade Federal de Minas Gerais / LNA )


Past webinars 316


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15/04 - 11:00 am BRT

LIneA Workshop ( LIneA )

On the Future of Data Centers and eScience Institutes: Celebrating LIneA’s 10th Anniversary

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.

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08/04 - 11:00 am BRT

Santiago Àvila ( Universidad Autónoma de Madrid )

The effect of the galaxy-halo connection on galaxy clustering in the advent of stage-IV experiments

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.

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01/04 - 11:00 am BRT

Tilman Troester ( Royal Observatory, Edinburgh )

Cosmology with the Kilo-Degree Survey

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.

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25/03 - 04:00 pm BRT

David Latham ( Harvard-Smithsonian Center for Astrophysics )

TESS - Transiting Exoplanet Survey Satellite

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.

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18/03 - 11:00 am BRT

Eduardo Janot Pacheco ( Universidade São Paulo )

The PLATO mission: Brazil chasing exoplanets

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.

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11/03 - 11:00 am BRT

Sunil Mucesh ( University College London )

A machine learning approach to galaxy properties: Joint redshift-stellar mass PDFs with Random Forest

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.

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04/03 - 01:00 pm BRT

Leanne Guy ( Vera Rubin Observatory )

Opportunities for Early Science with Rubin/LSST

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.