A Survey of Local Group Galaxies Currently Forming Stars. II. UBVRI Photometry of Stars in Seven Dwarfs and a Comparison of the Entire Sample

2007 
We have obtained UBVRI images with the Kitt Peak National Observatory and Cerro Tololo Inter-American Observatory 4 m telescopes and Mosaic cameras of seven dwarfs in (or near) the Local Group, all of which have known evidence of recent star formation: IC 10, NGC 6822, WLM, Sextans B, Sextans A, Pegasus, and Phoenix. We construct color-magnitude diagrams (CMDs) of these systems, as well as neighboring regions that can be used to evaluate the degree of foreground contamination by stars in the Milky Way. Intercomparison of these CMDs with those of M31, M33, the LMC, and the SMC permits us to determine improved reddening values for a typical OB star found within these galaxies. All of the CMDs reveal a strong or modest number of blue supergiants. All but Pegasus and Phoenix also show the clear presence of red supergiants in the CMD, although IC 10 appears to be deficient in these objects given its large Wolf-Rayet star population. The bright stars of intermediate color in the CMD are badly contaminated by foreground stars (30%-100%), and considerable spectroscopy is needed before statistics on the yellow supergiants in these systems will be known. This study is intended to serve as both the impetus and "finding charts" for further space-based imaging and for many spectroscopic programs at large aperture.
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