Homogeneous Photometry for Star Clusters and Resolved Galaxies. I. A Survey of Bright Stars in the Fornax Dwarf Spheroidal Galaxy

摘要

We present accurate photometry on the Johnson B, Kron-Cousins R photometric system for approximately 100,000 stars in a 1/3 deg~2 field centered on the dwarf spheroidal galaxy in Fornax. We identify numerous probable short-period variable stars, blue stars that appear to be the main sequence of a small population with an age of order 10~8 yr, and tow distinct types of luminous red star: an extended sequence of primarily carbon stars and a clump of mostly M giants slightly more luminous than the giant-branch tip. The spatial distribution of each of these subpopulations within the Fornax dwarf galaxy is considered.