Color-magnitude diagram for the Andromeda ii dwarf galaxy

Abstract

A color-magnitude diagram for the dwarf galaxy Andromeda II (And II) is presented, based on CCD photometry obtained using the Palomar 5 m telescope and Thuan-Gunn g, r filters. The mean metallicity, the metallicity spread, and the distance to And II are estimated. The mean metallicity of the galaxy is found to be 〈[Fe/H]〉 = -1.59+0.44-0.12 derived by superimposing globular cluster giant branches. This metallicity is consistent with the accepted MV vs [Fe/H] relationship for dwarf spheroidals. The spread in metallicity seems to be large, σ∼0.43, but we cannot determine the exact value. Andromeda II is estimated to be at a distance of 583+124-103 Kpc, ∼ 120 Kpc closer than M31.