Speaker

Mauro Barbieri

Title

Trilegal – New improvements (University of Padua)

Abstract

In this talk I will present the new improvements that I have added to stellar population synthesis code TRILEGAL : extinction model, binary evolution, variable stars, asteroseismic parameters, planet populations and their probability of detection. I will present also the results of a study of giant stars observed by CoRoT and how TRILEGAL can be used on ensemble asteroseismology studies.

Speaker

Bruno Coelho

Title

Beneath the Morphology of Quasi-stellar Objects (CAAUL, University of Lisboa)

Abstract

In the framework of the unified theory the classification of AGNs is largely a matter of line-of-sight perspective. Naturally a less schematic classification must consider the object interaction and merger history, dust contents, star formation waves, the rate and gyro direction of the central massive black hole, and the enrichment of the off accretion disk shells or regions. Nonetheless the entrusted relationship between the mass of the central black hole, its luminosity, and the mass and luminosity of the host galaxy must generally hold. Since by optical ground observations quasars are essentially quasi stellar objects, an apparent paradox hence arises by which the more massive and luminous a host galaxy is, the more luminous the quasar tends to be, thus making the more invisible by contrast the host galaxy. The presence of the host galaxy can be inferred also from color studies and from departures of the compound PSF of quasar and host galaxy to the purely pointlike stellar PSFs. This methodology can be used to classify morphologically the quasars observed out the atmosphere, as will be the case of the Gaia mission, enabling to derive a centroid astrometrically more precise than if a stellar PSF would have been applied for the centroid determination. We present the methodology to calculate morphological indexes, the observational programs in course, and a comprehensive analysis of images from the SDSS QSO catalogue.

Speaker

Daniel Thomas

Title

Galaxy evolution with BOSS (University of Portsmouth)

Abstract

I will give a brief overview over the BOSS/SDSS-III survey and its potential for galaxy evolution studies. I will particularly focus on our recent work on characterising the emission line and kinematic properties of BOSS galaxies, and their use to study the dynamical and dark matter properties of massive galaxies with look-back time.

Speaker

Will Percival

Title

Cosmological Measurements from Galaxy Clustering (University of Portsmouth)

Abstract

First results are presented from galaxy clustering measurements in the Baryon Oscillation Spectroscopic Survey (BOSS), which is part of SDSS-III. Data release 9, which was publicly released in July, contains 327,349 massive galaxies with an effective redshift z=0.57 covering 3,275 square degrees. Assuming a concordance LCDM cosmological model, this is equivalent to 0.77 h^{-3} Gpc^3, and represents the largest sample of the Universe ever surveyed at this density. In addition to reviewing the physics behind these techniques, I will present results from Baryon Acoustic Oscillation (BAO), Redshift-Space Distribution (RSD) measurements. I will then look ahead to future projects.

Speaker

David Gerdes

Title

Photometric Redshifts Using Boosted Decision Trees (University of Michigan)

Abstract

Photometric redshifts are essential to the next generation of large optical surveys, including DES, as the number of galaxies that will be observed far exceeds the ability to measure redshifts spectroscopically. Techniques for measuring photometric redshifts generally fall into two categories: template-based methods, and empirical or training-set-based methods. In this talk I will describe an empirical method, ArborZ, based on a machine-learning technique called Boosted Decision Trees. I will describe the training procedure and present results of the algorithm on SDSS data. I will also discuss the algorithm’s performance in the realistic case when the properties of the training set and the target photometric set differ. I’ll conclude with implications for DES.

Speaker

Alberto Krone-Martins

Title

Unsupervised Photometric Membership Assignment in Stellar Clusters (University of Lisboa)

Abstract

One of the most ancient problems in the photometric study of stellar clusters is the assignment of membership for its stars. Although several approaches exist for attacking this problem, they usually involve the adoption of complex theorethical models for the photometric data (isochrones) and/or the selection and use of control fields, possibly biasing some results. We have developed a data-driven, fully automated and unsupervised method to perform membership assignment in Stellar Clusters using photometric and spatial data, which is independent from complex theorethical models, as well as from the adoption of observational control fields. Our method is based on an iterative solution, and relies on Principal Component Analysis, clustering algorithms and kernel density estimations. Optionally, it also allows the user to take into account error models and missing data. We will present a description of the method, results obtained with its application to a set of realistic simulations as well as results obtained from analysis of real data of selected Open Clusters.

Speaker

Eduardo Ogasawara

Title

An Algebraic and Parallel Approach for Scientific Workflows using Chiron (CEFET/RJ & COPPE/UFRJ)

Abstract

Large-scale scientific experiments based on computer simulations are typically modeled as scientific workflows, which facilitate the sequencing of different programs. These scientific workflows are defined, executed and monitored by Scientific Workflow Management Systems (SWfMS). As these experiments manage large amounts of data, it is interesting, if not essential, to execute them in High Performance Computing (HPC) environments, such as clusters, grids and clouds. However, few SWfMS provide parallel support and they usually lack a run-time provenance support mechanism. Also, the existing parallel SWfMS have limited primitives to optimize workflow execution. To address these issues, we developed an algebraic approach to specify the scientific workflow, and it leaded to the implementation of Chiron: An Algebraic-Based parallel scientific workflow engine. Chiron has a native distributed provenance gathering mechanism and can perform algebraic transformations to obtain better execution strategies. Chiron is efficient in executing scientific workflows, with the benefits of bringing room for declarative specification and run-time provenance support.

Speaker

Michael Bucha

Title

Modeling the Dark Energy Survey (University of Zurich)

Abstract

The Dark Energy Survey (DES) is a project to map out galaxies in 5000 sq deg of the southern sky with the intent of providing tighter constraints on the nature of dark energy using, among other methods, galaxy clusters, weak lensing, and baryon acoustic oscillations. DECam, a wide field camera constructed for the project, recently saw first light and is currently undergoing commissioning. As the beginning of the survey is now imminent, the DES project is in its final stages of preparing for the incoming data. One aspect of this is a project known as the Blind Cosmology Challenge (BCC). The BCC is an ambitious project designed to test our ability to accurately extract cosmology from the DES data set by means of running the cosmological analysis pipeline on a set of synthetic galaxy catalogs designed to model the predicted DES galaxy catalog. A suite of these catalogs are being created using a range of underlying cosmologies. In this talk, I will review the ongoing efforts to create these synthetic, wide area galaxy catalogs, that probe the full range of environments and scales we anticipate the survey to probe. This is a challenging project that requires realistically modeling a wide range of galaxy properties, such as photometry, clustering, shape noise, and lensing effects. Additionally, I will present some initial results from evaluating the behavior of cluster finders on such catalogs.

Speaker

Carlos Cunha

Title

Problemas radiais e angulares em estudos cosmológicos de grandes escalas (University of Stanford)

Abstract

Esta apresentação será dividida em duas partes. Parte I: Requerimentos para a calibragem angular em estudos de estrutura de grande escala. O agrupamento de galaxies em grande escala é rico em informações sobre a origem e composição do Universo. Porem, é muito difícil quantificar a seleção da amostra coletada durante vários anos em uma vasta área do céu. Nessa palestra, apresentarei um formalismo para estimar os erros sistemáticos induzidos por efeitos na selecao da amostra e identificarei os requerimentos para a calibragem do Dark Energy Survey (DES). Parte II: Requerimentos para acompanhamento espectroscópico de estudos fotométricos. Redshifts são uma propriedade essencial em cosmologia. Por limitações de tempo e dinheiro, estudos cosmológicos fotométricos dependem de estimativas intrinsincamente imprecisas de redshifts, os chamados photo-zs. Os photo-zs nao devem ser utilizados em analises cosmológicas a menos que as incertezas sejam quantificadas com precisão. Tipicamente, as incertezas sao caracterizadas usando uma amostra de galaxias com redshifts determinados espectroscopicamente. Porem, redshifts espectroscopicos nao sao perfeitos, e as amostras são incompletas e contem redshifts incorretos. Nessa palestra, descreverei problemas em amostras de redshifts espectroscopicos e como utiliza-los para a calibragem de erros de redshifts fotométricos.

Speaker

Rodney Gomes

Title

Origem dos TNO’s: o que sabemos e o que resta saber (Observatório Nacional)

Abstract

G. Kuiper previu que deveria existir um disco de objetos de gelo além da órbita de Netuno. Estes corpos seriam remanescentes do disco de planetesimais original, cujos componentes não conseguiram se aglutinar para formar planetas por ser a região trans-netuniana pouco densa para promover uma acreção de planetesimais até o tamanho planetário. Este disco deveria ser dinamicamente frio (órbitas pouco excêntricas e pouco inclinadas), poderia se extender até ~ 100 UA e teria ter uma massa total em torno de algumas massas da terra. Embora a descoberta dos primeiros objetos do Cinturão de Kuiper tenha parcialmente satisfeito a previsão de G. Kuiper, na verdade as órbitas dos TNO’s se mostraram bem diferentes do esperado, ou seja, excêntricas, inclinadas e com uma borda externa em torno de 50 UA. Além disso, a massa total estimada para o Cinturão de Kuiper certamente está abaixo de 0.1 massa da Terra e existem fortes evidências da existência de duas populações distintas dentro do Cinturão. Neste seminário, estarei apresentando o que já foi desenvolvido para explicar a peculiar estrutura orbital do Cinturão de Kuiper e sua relação com a evolução primordial do Sistema Solar. Estarei, ainda, discorrendo sobre os pontos ainda não totalmente esclarecidos da estrutura dinâmica dos TNO’s e os cenários que estariam por detrás da possível explicação desses pontos.

Speaker

Roberto Cid Fernandes

Title

Galaxy growth in 1 and 2D: 1st results from the CALIFA survey (UFSC & IAA-Granada)

Abstract

Spectral synthesis of galaxies is the science/art of digging as much information as possible from galaxy spectra. In the last decade, evolutionary synthesis models with decent spectral resolution in the optical have promoted huge advances in this area, which, combined with the avalanche of data has lead to substantial progress in our understanding of galaxies. The STARLIGHT code is one such tool in this business. It performs Angstrom-by-Angstrom fits of galaxy spectra combining models of simple stellar populations of various ages and metallicities. It has been employed to address a variety of issues, from problems where one seeks information on stellar population mixtures (a.k.a. Star Formation Histories), to others where one is more interested in getting rid of stellar light in order to measure emission lines, to study stellar kinematics, and even to test the ingredients (SSP models) themselves. This talk will (1) briefly review the basics of spectral synthesis and illustrate its power as a tool to study galaxy evolution in 1D (ie, SDSS-like integrated spectra), and (2) move on to the main course: We will present the 1st results of the application of STARLIGHT to the 1st 100 galaxies observed in the CALIFA survey. CALIFA is collecting data cubes (integral field spectroscopy) for 600 galaxies (~ 1000 spectra per target) spread over the color magnitude diagram. Besides its own importance, this pioneer IFS survey serves as a test-bed for future projects, like SAMI and MaNGA. We have developed an end-to-end pipeline to processes data cubes through STARLIGHT, thus allowing us to resolve galaxies in time and space. Dissecting galaxy spectra as a function of position is showing us how the different morphological components of galaxies build their mass and metals over time, and promises to provide important clues for galaxy evolution models in general.

Speaker

Eduardo Bezerra

Title

Aplicações da Computação para Astronomia: Mineração de Dados e Simulação (CEFET/RJ)

Abstract

O grande volume de dados acumulado por observações em Astronomia tem suscitado a demanda por técnicas computacionais para descobrir padrões e tendências relevantes subjacentes a esses dados. De outro lado, esses mesmos dados acumulados permitem a identificação de parâmetros da dinâmica de alguns fenômenos físicos astronômicos de tal forma que esses parâmetros podem ser usados para a produção de simulações computacionais dos fenômenos. Nesse seminário, são apresentadas introduções a algumas técnicas de mineração de dados e de simulação computacional, e são apresentadas possibilidades de aplicação dessas técnicas para suporte à Astronomia.

Speaker

Thiago Gonçalves

Title

O estudo de galáxias Lyman break em baixo redshift (--)

Abstract

Speaker

Eduardo Balbinot

Title

FindSat – Hunting for sparse structures in the halo (UFRGS, LineA)

Abstract

The census of MW satellites and their distribution as a function of Galactocentric distance, mass, metallicity among other properties, will help recover the history of mass assembly in our Galaxy and test structure formation scenarios.The Milky Way has two distinct groups of satellite galaxies when we consider their year of discovery. 9 satellites were known up to the 1970s. About 15 new small galaxies were discovered with the wide and homogeneous surveys from the past 15 years, such as SDSS and 2MASS. The Dark Energy Survey (DES) is anticipated to lead to the detection of dozen more such systems, assuming that their stellar nature can be distinguished from the much larger number of galaxy clusters to be sampled. With this goal in mind we are developing FindSat, an algorithm that searches for new satellite galaxy and star clusters candidates as overdensities of stellar sources in a large photometric survey. FindSat was validated using SDSS DR7 data and successfully recovered all previously identified MW satellites with these data. It was then applied to DR8 data in the Southern Galactic region of the BOSS survey. 30 candidates were found, for which deeper follow up images from CFHT are being taken. We will present our very preliiminary results from these new images, including one already confirmed new MW satellite.

Speaker

Karin Menendez

Title

Galáxias Submilimétricas – Uma População Enigmática Em Alto Redshift (Observatório do Valongo)

Abstract

Galáxias ultraluminosas no infravermelho (L>1012Lsolar; ULIRGs) são raras no universo local, mas dominam a densidade de energia co-móvel em alto redshift (z>2). Devido à grande abundância de poeira, muitas destas ULIRGs são fracas no óptico e foram descobertas apenas recentemente devido à emissão térmica da poeira em comprimentos de onda submilimétricos. Estudos detalhados das chamadas galáxias submilimétricas (SMGs) revelam: morfologias complexas associadas a mergers; taxas de formação estelar de até 1000 vezes a taxa na Via Láctea; e a presença de núcleos ativos (AGN) que indica a coexistência de formação estelar intensa com o crescimento rápido de buracos negros supermassivos. Com um redshift médio de z~2 e a capacidade de formar o grosso da massa estelar de uma galáxia elíptica em ~108 anos, as SMGs são candidatas viáveis a progenitoras das galáxias de maior massa no universo local. Assim, estes objetos formam uma população extremamente interessante para o estudo da parcela mais massiva em modelos atuais de formação e evolução de galáxias. Apresentarei uma revisão breve do que conhecemos sobre estas galáxias e compartilharei alguns dos resultados mais recentes baseados em dados H-alpha coletados com o espectrógrafo de campo integral OSIRIS no telescópio Keck, Hawaii. Este instrumento foi construído para funcionar com o sistema de Óptica Adaptativa com Estrela Laser que permite uma resolução até 10 vezes maior que estudos anteriores limitados pelo seeing atmosférico. Portanto, estes resultados são nossa primeira visão detalhada da distribuição do gás ionizado nas SMGs. Estudos como estes nos preparam para uma nova era de detalhe na distribuição de combustível molecular em galáxias no alto redshift com o ALMA.

Speaker

Rogério Rosenfeld

Title

The Discovery of a New Boson at the LHC (IFT-Unesp)

Abstract

In this talk I’ll describe how the long-sought Higgs boson of the Standard Model was finally found at the LHC.

Speaker

Antônio Guimarães

Title

Descrição (sem energia escura) da Expansão Cósmica (UFRJ)

Abstract

The apparent magnitude and redshift of type Ia supernovae provide currently the most stringent constraints on the cosmic expansion history. We study alternative ways to describe the cosmic expansion that are independent of dark energy models and even independent of assumptions about the energy contend of the universe and the underlying gravitational theory. One first approach was to use kinematic models for the cosmic expansion, where we found that even very simple models allow for data fittings that are as good as.