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We have obtained Keck Low Resolution Imaging Spectrograph images in V and I of the newly discovered Local Group dwarf galaxies Pegasus dSph and Cassiopeia dSph and their surrounding field. The first stellar luminosity functions and color-magnitude diagrams are presented for stars with V <~ 25 and I <~ 24. The distances to the new dwarfs are estimated from the apparent I mag of the tip of the red giant branch to be: D_MW (Peg dSph) = 830 +/- 80 kpc and D_MW (Cas dSph) = 760 +/- 70 kpc, consistent with their belonging to the extended M31 satellite system. Both galaxies are dwarf spheroidals (dSphs) with red giant branch morphologies indicating predominantly old stellar populations and estimated mean metallicities, <[Fe/H]>, of -1.3 +/- 0.3 for Peg dSph and -1.4 +/- 0.3 for Cas dSph. Their central surface brightness-<[Fe/H]>-absolute magnitude relationship follows that of other Local Group dSphs, dwarf ellipticals, and dwarf irregulars. In contrast to four out of nine Milky Way dSphs (the four that lie beyond D_MW =100 kpc), none of the six known M31 dSphs appears to have a dominant intermediate-age population.
We report the results of VLT and Keck adaptive optics surveys of known members of the Eta Chamaeleontis, MBM 12, and TW Hydrae (TWA) associations to search for close companions. The multiplicity statistics of Eta Cha, MBM 12, and TWA are quite high c
We discuss the detection limits and current status of a uniform survey of SDSS I for ultra-faint Milky Way dwarf galaxies. We present the properties of two new, low surface brightness Milky Way companions discovered as a result of this survey. One of
We present radial velocities for 14 stars on the California & Carnegie Planet Search target list that reveal new companions. One star, HD 167665, was fit with a definitive Keplerian orbit leading to a minimum mass for the companion of 50.3 Mjup at a
We report on an investigation of the SBS 1520+530 gravitational lens system and its environment using archival HST imaging, Keck spectroscopic data, and Keck adaptive-optics imaging. The AO imaging has allowed us to fix the lens galaxy properties wit
We present a deep, wide-field photometric survey of the newly-discovered Hercules dwarf spheroidal galaxy, based on data from the Large Binocular Telescope. Images in B, V and r were obtained with the Large Binocular Camera covering a 23 times 23 fie