NOAO >   Observing Info >   Approved Programs >   2003B-0254

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Proposal Information for 2003B-0254


PI: Puragra Guhathakurta, UCO/Lick Obs, UC Santa Cruz, raja@ucolick.org
Address: 1156 High Street, Santa Cruz, CA, 95064, USA

CoI: Jennifer Johnson, Herzberg Institute of Astrophysics
CoI: Roeland van der Marel, Space Telescope Science Institute
CoI: Joris Gerssen, Space Telescope Science Institute
CoI: Eva Grebel, MPIA Heidelberg
CoI: Daniel Harbeck, MPIA Heidelberg
CoI: David Crampton, Herzberg Institute of Astrophysics

Title: Dark Matter Halos of Dwarf Spheroidals: Andromeda VII

Abstract: Low luminosity dwarf galaxies appear to be the most Dark Matter dominated of all galaxies and, of these, the Dwarf Spheroidal galaxies (dSph) are the most extreme. Here, we propose to measure accurate radial velocities for about 60 red giants in And VII, the brightest of M31's dSph companions. By combining this sample with 20 stars with previously measured velocities (from our earlier Keck/HIRES experiment), we will have a sample of 75 stars, large enough to study the rotation and velocity dispersion of And VII as a function of radius. Coupled with dynamical modeling, these data will allow us to measure the dark matter profile of its halo and constrain possible formation scenarios. This is the first step towards determining whether the Milky Way dSphs are representative of this class of dwarf galaxies and to what extent their properties depend on environment.


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