Structure and Formation of Elliptical and Spheroidal Galaxies

New surface photometry of all known elliptical galaxies in the Virgo cluster is combined with published data to derive composite profiles of brightness, ellipticity, position angle, isophote shape, and color over large radius ranges. These provide enough leverage to show that Sersic log I alpha r(1/n) functions fit the brightness profiles I(r) of nearly all ellipticals remarkably well over large dynamic ranges. Therefore, we can confidently identify departures from these profiles that are diagnostic of galaxy Formation. Two kinds of departures are seen at small radii. All 10 of our ellipticals with total absolute magnitudes M(VT) <= -21.66 have cuspy cores-"missing light"-at small radii. Cores are well…