Found 41 talks archived in The Galaxy

Video
Thursday June 16, 2016
Mrs. Sara Bertran de Lis
Instituto de Astrofísica de Canarias (IAC)

Abstract

The detection of chemical inhomogeities in the Galactic disk requires an oustanding precision in the abundance measurements and a thorough estimation of the uncertainties. So far, studies in alpha-elements in disk stars either do not reach the required precision, or comprise too small samples in the solar neighborhood. Thanks to the Apache Point Galactic Evolution Experiment (APOGEE), we have for the first time a large spectroscopic sample of about 100.000 disk stars, with data homogeneously obtained, reduced, and analyzed. Taking advantage of such database, we examine the distribution of oxygen-to-iron abundance ratio in stars across the Galactic disk. These data reveal that the square root of the star-to-star cosmic variance in the [O/Fe] at a given metallicity is about 0.03 to 0.04 dex in both the thin- and thick-disk populations. Measuring the spread in [O/Fe] and other abundance ratios can provide strong constraints for models of Galactic chemical evolution. In this talk we will describe how we arrived at this result, the calculation of uncertainties, and implications regarding the chemical evolution of the Galaxy.

Video
Tuesday February 25, 2014
Dr. Carmela Lardo
INAF-Osservatorio Astronomico di Bologna

Abstract

In this talk I present an overview of the structure, activity and goals
of the Gaia-ESO survey, a large public spectroscopic survey aimed at investigating
the origin and formation history of our Galaxy by collecting high quality spectroscopy
of representative samples (about 105 Milky Way stars) of all Galactic stellar populations,
in the field and in clusters. Briefly, I discuss the most relevant results obtained so far.
In particular, I present our study on the internal kinematics of Galactic globular clusters based on the radial estimates obtained from the survey complemented with ESO archive data.


Video
Thursday February 6, 2014
Dr. Elena Pancino
INAF - Osservatorio Astronomico di Bologna

Abstract

Gaia - the ESA cornerstone astrometric mission - was launched in December 2013, with the goal of censing the Milky Way population in a 6D space (positions and velocity) of 10^9 point-like obects, with errors
100-1000 times smaller than Hipparcos, with three color magnitudes and spectra as well. The scientific impact of its data will be large in many fields of astrophysics, from Galactic science, to Solar system objects, to stellar astrophysics, to galaxies and Quasars; from the distance ladder revision to fundamental physics. I will describe the mission concept, the scientific goals, and the present status of the mission, with special attention to the flux calibration of Gaia data.


Video
Thursday January 9, 2014
Dr. Manuela Zoccali
Universidad Católica de Chile

Abstract

The structure, kinematics and stellar population of the Galactic bulge is very complex. Only three years ago the bulge was discovered to be X-shaped, a structure believed to originate from the dynamical instabilities of a disk, through the formation and posterior heating of a bar. The study of its kinematics reveals a cylindrical rotation, typical of a bar, suggesting the absence of a spheroidal component. Nevertheless, the bulge stellar population is old, has a radial metallicity gradient, and element ratio indicative of a short formation timescale. All these elements conflict with a simplistic view of the bulge as a heated bar, formed via "secular" evolution of a disk. I will review our knowledge of the bulge properties as traced by the 3D structure, kinematics, and chemical composition of its red clump stars.


Video
Friday September 6, 2013
Dr. Carlos Allende Prieto
Instituto de Astrofisica de Canarias, Tenerife, Spain

Abstract

3- Other spectroscopic surveys and analysis strategies

- eBOSS, BigBOSS, HETDEX, WEAVE, 4MOST

- data mashup: astrometry,  photometry and spectroscopy together

- reconstructing the Galaxy

- 'observing' galaxy simulations

- discovery and follow-up of interesting/exotic targets: HVS, UMPS, CEMPS, RCrBs...


Video
Friday September 6, 2013
Dr. Leo Girardi
Osservatorio Astronomico di Padova, INAF, Italy

Abstract

5- Some current problems and opportunities

- simulating kinematics

- simulating variables

- simulating non-solar scaled populations

- simulating rare and extreme populations (e.g. X-ray sources, PNe,

  hot-WDs, AGB-manque', C stars, IR-emission by mass-losing stars)

- opportunities opened by asteroseismology


Video
Friday September 6, 2013
Dr. Ortwin Gerhard
Max-Planck-Institut fuer extraterrestrische Physik, Germany

Abstract

5-   The Galactic halo

- mass, extent, shape

- substructure, inner/outer halo


Video
Friday September 6, 2013
Dr. Ken Freeman
Australian National University, Australia

Abstract

5- The Galactic bulge

- observational status on bulge kinematics and chemical properties in the context of other bulges

- ideas about the formation of the bulge


Video
Friday September 6, 2013
Dr. Jerry Sellwood
Rutgers University, USA

Abstract

5- SPH basics

- numerical viscosity

- Kelvin-Helmholtz instabilities

- other problems and their amelioration


Video
Thursday September 5, 2013
Dr. Carlos Allende Prieto
Instituto de Astrofisica de Canarias, Tenerife, Spain

Abstract

2- Spectra

- APOGEE, RAVE, SDSS/SEGUE/BOSS, Gaia-ESO

- Spectral classification

- radial velocities

- automated data analysis



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