A Survey for Low Surface Brightness Galaxies around M31. I. The Newly Discovered Dwarf Andromeda V

We present images and a color-magnitude diagram for And V, a new dwarfspheroidal companion to M31 that was found using a digital filtering techniqueapplied to 1550 square degrees of the second Palomar Sky Survey. And V resolvesinto stars easily in follow-up 4-m V- and I-band images, from which we deduce adistance of 810 +/- 45 kpc using the tip of the red giant branch method. Withinthe uncertainties, this distance is identical to the Population II distancesfor M31 and, combined with a projected separation of 112 kpc, provides strongsupport for a physical association between the two galaxies. There is noemission from And V detected in H alpha, 1.4 GHz radio continuum, or IRASbandpasses, and there is no young population seen in the color-magnitudediagram that might suggest that And V is an irregular. Thus, the classificationas a new dwarf spheroidal member of the Local Group seems secure. With anextinction-corrected central surface brightness of 25.2 V mag per squarearcsec, a mean metal abundance of [Fe/H] approximately -1.5, and no evidencefor upper AGB stars, And V resembles And I & III.