Dynamics and Chemical Evolution of M31's Halo and Dwarf Galaxies

Rutgers University New Brunswick, New Brunswick NJ

Investigators

Abstract

AST-0086308 Patrick Cote The aim of this project is to support a spectroscopic study of stars and dwarf galaxies in the halo of M31. These data would extend our detailed knowledge of stellar metallicities and kinematics in a systematic way beyond the stars in our own galaxy and its dwarf companions and provide valuable information for defining the basic parameters of the Local Group and for constraining theoretical pictures of galaxy formation and dynamics. M31 is both the dominant mass concentration in the Local Group and nearest large spiral galaxy. Thus, it offers a unique opportunity to study the fossil record of galaxy formation in a level of detail which will never be possible with high-redshift galaxies. This work will carry out a systematic study of the dynamics and chemical evolution of M31's stellar halo and its dwarf spheroidal galaxies based on spectroscopy of individual red giant branch stars measured with the Keck 10m telescopes. Specific goals of the program include: (1) a direct measurement of the angular momentum of the M31 stellar halo using radial velocities for several hundred halo field stars; (2) a measurement of the mass of M31's dark halo on scales of several hundred kiloparsecs based on the radial velocities of its outlying satellites; (3) a spectroscopic study of the chemical abundances of stars belonging to these satellites; and (4) a dynamical survey of the dark matter content in these faint galaxies. Funding for this project was provided by the NSF program for Extragalactic Astronomy & Cosmology (AST/EXC). ***