Stellar Populations in M31: Resolved V,I Photometry of Five Halo Globular

Abstract

We present V,I CCD photometry of individual stars in five halo globular clusters in M31. For four clusters, the CMD shows a well-defined giant branch whose morphology is consistent with the metallicity estimates from spectroscopy of the clusters integrated light. An area of ∼10 square arcmin of the halo of M31 has also been analyzed. The mean halo metallicity is [Fe/H]∼-0.5 with a large dispersion σ<SUB>[Fe/H]</SUB>∼.5 dex. The distance modulus has also been estimated as (m-M)<SUB>0</SUB>=24.5±0.2, close to the more usual value of (m-M)<SUB>0</SUB>∼24.3.