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Research on the Milky Way and nearby galaxies at UCSC covers a wide range of topics, including the star formation and the interstellar medium, stellar evolution, and stellar populations.
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SPECTROSCOPIC & PHOTOMETRIC LANDSCAPE OF ANDROMEDA'S STELLAR HALO
Our group at UCSC has been leading the SPLASH survey of red giant stars in our closest largest neighbor, the Andromeda spriral galaxy (M31; see image below). We have developed a sensitive method for identifying rare red giants in the remote outskirts of M31. Studies of stellar kinematics, chemical abundance, and age distritbution are used to investigate the merger history of M31's halo, tidal disruption of dwarf satellites, the dark matter content of M31 and its satellites, and Local Group dynamics.
The background image shows the Andromeda spiral galaxy (M31) and its two closest dwarf satellites NGC205 and M32. Our group is leading the SPLASH project, a large survey of individual red giant stars in M31 (top left inset). Using a combination of several photometric and spectroscopic diagnostics, we have discovered red giant stars in the remote outskirts of M31 (r >~ 150 kpc). The resulting surface brightness profile is shown in the top right inset. M31's angular diameter is at least 25 degrees, which is 50 full moon diameters across or twice the size of the "W" in the Cassiopeia constellation.