Title: The Assembly History of Elliptical Galaxies

Richard Ellis
Caltech


Abstract:

The regular morphology and uniform stellar populations observed in local
elliptical galaxies suggests a deceptively simple assembly history
consistent with a monolithic collapse at early times. In contrast,
numerical simulations and dark matter-based models of structure formation
suggest most massive ellipticals formed via the late mergers of young
star-forming disk galaxies. Recent models make quite specific predictions
about rate of mass assembly over the redshift range 0 < z < 2. Using the
combination of HST imagery and high signal/noise Keck spectroscopy, I will
demonstrate that both the comoving abundance and mass assembly rate of
elliptical galaxies observed at z=1 suggests most of the stellar mass
was in place at z=2, in marked contrast to popular models of structure
formation. The prospects for extending this work will be briefly discussed.