Schedule Feb 17, 2012
Challenges in Finding the Milky Way's Faintest Companions: Star-Galaxy Separation
Ross Fadely (Haverford)

The discovery and characterization of the population of Milky Way satellites is a crucial test of Cold Dark Matter and galaxy formation physics. A thorough census of these faint dwarfs will rely on discovery and follow-up data which reaches optical depths (much) deeper than r ~ 23 mag. At these magnitudes the number of unresolved galaxies can overwhelm star counts, potentially rendering the discovery of new satellites impossible. We show photometric star-galaxy can dramatically improve this picture, and present a new hierarchical Bayesian method which outperforms maximum likelihood techniques. Finally, we discuss implications for the discovery of new dwarfs in upcoming surveys like DES, PanSTARRS, and LSST.


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