ON THE CONNECTION BETWEEN SHAPE AND STELLAR POPULATION IN EARLY-TYPE GALAXIES

D'Onofrio, M.; Valentinuzzi, T.; Fasano, G.; Moretti, A.; Bettoni, D.; Poggianti, B.; Vulcani, B.; Varela, J.; Fritz, J.; Cava, A.; Kjaergaard, P.; Moles, M.; Couch, W. J.; Dressler, A.
2011
ASTROPHYSICAL JOURNAL LETTERS
DOI
10.1088/2041-8205/727/1/L6
We report on the discovery of a relation between the stellar mass M* of early-type galaxies (hereafter ETGs), their shape, as parameterized by the Sersic index n, and their stellar mass-to-light ratio M*/L. In a three-dimensional log space defined by these variables, the ETGs populate a plane surface with small scatter. This relation tells us that galaxy shape and stellar population are not independent physical variables, a result that must be accounted for by theories of galaxy formation and evolution.