The SPLASH Survey: Internal Kinematics, Chemical Abundances
Draft version October 29, 2018 Preprint typeset using LATEX style emulateapj v. 2/19/04 THE SPLASH SURVEY: INTERNAL KINEMATICS, CHEMICAL ABUNDANCES, AND MASSES OF THE ANDROMEDA I, II, III, VII, X, AND XIV DSPHS1,2 Jason S. Kalirai3, Rachael L. Beaton4, Marla C. Geha5, Karoline M. Gilbert6,7, Puragra Guhathakurta7, Evan N. Kirby7,8,9, Steven R. Majewski4, James C. Ostheimer4, Richard J. Patterson4, and Joe Wolf10 Draft version October 29, 2018 ABSTRACT We present new Keck/DEIMOS spectroscopic observations of hundreds of individual stars along the sightline to Andromeda’s first three discovered dwarf spheroidal galaxies (dSphs) – And I, II, and III, and leverage recent observations by our team of three additional dSphs, And VII, X, and XIV, as a part of the SPLASH Survey (Spectroscopic and Photometric Landscape of Andromeda’s Stellar Halo). Member stars of each dSph are isolated from foreground Milky Way dwarf and M31 field contamination using a variety of photometric and spectroscopic diagnostics. Our final spectroscopic sample of member stars in each dSph, for which we measure accurate radial velocities with a median uncertainty (random plus systematic errors) of 4 – 5 km s−1, includes 80 red giants in And I, 95 in And II, 43 in And III, 18 in And VII, 22 in And X, and 38 in And XIV. The sample of confirmed members in the six dSphs are used to derive each system’s mean radial velocity, intrinsic central velocity dispersion, mean abundance, abundance spread, and dynamical mass. This combined data set presents us with a unique opportunity to perform the first systematic comparison of the global properties (e.g., metallicities, sizes, and dark matter masses) of one-third of Andromeda’s total known dSph population with Milky Way counterparts of the same luminosity.
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