Insights On The Formation, Evolution, And Activity Of Massive Galaxies From Ultracompact And Disky Galaxies At Z=2-3

We present our results on the structure and activity of massive galaxies at z = 1-3 using one of the largest (166 with M-star >= 5 x 10(10) M-circle dot) and most diverse samples of massive galaxies derived from the GOODS-NICMOS survey: (1) Sersic fits to deep NIC3 F160W images indicate that the rest-frame optical structures of massive galaxies are very different at z = 2-3 compared to z similar to 0. Approximately 40% of massive galaxies are ultracompact (r(e) 2. The large fraction of n 2. In order for massive galaxies at z = 2-3 to evolve into present-day massive E/S0s, they need to significantly increase (n, r(e)). Dry minor and major mergers may play an important role in this process.HST from STScI GO-11082Norman Hackerman Advanced Research Program (NHARP) ARP-03658-0234-2009National Aeronautics and Space Administration (NASA) LTSA NAG5-13063NSF AST-0607748DFGSTFCLeverhulme FoundationNASA NAS5-26555NASA Office of Space Science NAG5-7584Particle Physics and Astronomy Research Council (UK)Australian Research Council (AUS)Astronom