The Sagittarius dwarf galaxy as seen by the VLT/FLAMES facility
Abstract
This is the first report of the use of the VLT FLAMES facility on the local group dwarf galaxy Sagittarius (SGR). The observing program aimed at collecting a large sample of high-resolution spectra with two main goals: (1) to obtain a detailed description of SGR metallicity distribution, and (2) to study the internal dynamics of SGR, its Mass and Mass to Light ratio (M/L). With the present work, we confirm the existence of a metal-rich population, extending above solar metallicity. The main component of SGR stars is peaked at [Fe/H]∼ -0.5, while we found evidence, for the first time, of a metal-weak tail in the SGR populations, considerably more metal-weak than M54 ([Fe/H]∼ -1.5). Our direct measure of the central velocity dispersion of SGR give sigma =8.2±0.3 km s-1 which translates in an M/L=12.5 using current values of the SGR structural parameters. This new value is in good agreement with the accretion self-consistent ``model II'' of \cite{HW01}.
Based on Observations collected at the VLT- Publication:
-
Memorie della Societa Astronomica Italiana Supplementi
- Pub Date:
- 2004
- Bibcode:
- 2004MSAIS...5..291Z
- Keywords:
-
- Dwarf Galaxies;
- Kinematics;
- Chemical Abundances