Fine structure of the red clump in Local Group galaxies

Abstract

Some fine structures can nowadays be identified in the high-quality colour-magnitude diagrams (CMD) of Local Group galaxies. The clump of red giants, for instance, may present a significant colour spread, and extensions to both brighter and fainter luminosities. Such features are predicted by population synthesis models which consider stars in the complete relevant ranges of ages and metallicities, and are potentially useful for constraining the star formation histories of the parent galaxies over scales of gigayears. We briefly comment the cases of fields in the Magellanic Clouds, M31, and the local CMD from Hipparcos.Comment: To appear in Proc. of the VLT Opening Symposium (Parallel Workshop 2: Star-Way to the Universe