Studying the Stellar Populations of the Local Group with VLT

The power of high quality imaging combined with the large collecting area of each VLT telescope is impressive, and there are clearly many exciting discoveries waiting to be made. The study of resolved stellar populations will certainly benefit greatly from this new observatory, as with Palomar before. We will now be able to probe a much large range of star forming environment within the Local Group, and specifically very low metallicity regions in nearby dwarf irregular galaxies. The study of individual stars and star-formation regions in the nearby universe is the only way we will understand the observations of galaxy populations at high redshift. We present some initial results from the BVI imaging of the Local Group galaxy Antlia made during FORS1 science verification in January 1999.Comment: To appear in the proceedings of the VLT Opening Symposium, held in Antofagasta, Chile in March 199

UVES Abundances of Stars in Nearby Galaxies: How Good are Theoretical Isochrones?

Here we report some results from an ESO-VLT programme to observe individual stars in nearby dwarf galaxies at high resolution with the UVES spectrograph (Tolstoy, Venn, Shetrone, Primas, Hill, Kaufer & Szeifert 2002, submitted to AJ). We mainly concentrate on illustrating the issues and uncertainties surrounding our efforts to determine the ages of stars for which we have accurately measured [Fe/H] and [alpha/Fe].Comment: 2 page contribution to conference "New Horizons in Globular Cluster Astronomy", Padua, June 2002 ed. G. Piotto, G. Meylan, G. Djorgovski, & M. Riello, ASP Conf. Ser. (2002

The Optical Velocity of the Antlia Dwarf Galaxy

We present the results of a VLT observing program carried out in service mode using FORS1 on ANTU in Long Slit mode to determine the optical velocities of nearby low surface brightness galaxies. Outlying Local Group galaxies are of paramount importance in placing constraints the dynamics and thus on both the age and the total mass of the Local Group. Optical velocities are also necessary to determine if the observations of HI gas in and around these systems are the result of gas associated with these galaxies or a chance superposition with high velocity HI clouds or the Magellanic Stream. The data were of sufficient signal-to-noise to obtain a reliable result in one of the galaxies we observed - Antlia - for which we have found an optical helio-centric radial velocity of 351 $\pm$ 15 km/s.Comment: 11 pages, 4 figures, 5 tables MNRAS, in pres

The chemical composition of Local Group dwarf spheroidals

I will review the progress of VLT spectroscopy of large numbers of individual stars in nearby dwarf spheroidal galaxies. This spectroscopy has allowed us to obtain detailed insights into the chemical and dynamical properties of the resolved stellar population in these nearby systems.Comment: 8pages, 6 figures. Invited talk to appear in the proceedings of the IAUC198 Coll. "Near-Field Cosmology with Dwarf Elliptical Galaxies", H. Jerjen & B. Binggeli (eds.

The Local Group: Inventory and History

My presentation was an overview of what we know about the Local Group of galaxies, primarily from optical imaging and spectroscopy. AGB stars are on the whole a very sparse and unrepresentative stellar population in most Local Group galaxies. However, more detailed studies of star formation histories and chemical evolution properties of populations, like Main Sequence dwarf stars and Red Giant Branch stars, allow a better understanding of the evolutionary context in which AGB stars can be observed. There are a variety of galaxy types in the Local Group which range from predominantly metal poor (e.g., Leo A) to metal-rich (e.g., M 32). Dwarf galaxies are the most numerous type of galaxy in the Local Group, and provide the opportunity to study a relatively simple, typically metal-poor, environment that is likely similar to the conditions in the early history of all galaxies. Hopefully the range of star formation histories, peak star formation rates and metallicities will provide enough information to properly calibrate observations of AGB stars in more distant systems, and indeed in integrated spectra. Here I will summarise what we know about the star formation histories of nearby galaxies and their chemical evolution histories and then attempt to make a connection to their AGB star properties.Comment: Invited Review, "Why Galaxies Care About AGB Stars II", eds. Franz Kerschbaum, Thomas Lebzelter, and Bob Wing, Vienna, August 2010, 10 pages, 6 figure

Milky Way and resolved stellar pop

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