RUI: Stellar Populations in Nearby Dwarf Galaxies

Seattle University, Seattle WA

Investigators

Abstract

The goals of this project are to understand the assembly of the Milky Way, the assembly of its halo, and the behavior of dark matter halos in dwarf galaxies. The observations target dwarf galaxies in the Local Group which have been discovered by the Sloan Digital Sky Survey (SDSS). These faint, low-density, spheroidal, systems have experience tidal interactions and their stellar populations are stirred up. Another target is the apparently less disturbed, irregular Wolf-Lundmark-Melotte (WLM) galaxy that is more remote from the Milky Way's dark matter halo. The observations may help to distinguish between primordial objects made in dark matter halos, and objects formed in tidal interactions between galaxies. A large number of stars in the fields of these newly discovered dwarfs ystems has already been observed with the Apache Point Observatory (APO) 3.5m and the CTIO 4-m telescopes. Here the Washington and Stromgren photometry of stellar populations is completed and analyzed to obtain stellar metallicities and ages. Additional low-resolution spectroscopy is used to further probe metallicities, and check on the memberships of the observed stars. In turn, this information constrains the initial mass functions and star formation histories of these faint dwarf systems. This project supports research at an undergraduate institution and will introduce several undergraduate students to scientific research.