Alan Stockton
University of Hawaii
 

"Morphologies of Massive Galaxies with Old Stellar Populations at High Redshifts"
 

I will describe our program to identify and investigate luminous galaxies with old stellar populations in the fields of radio sources at high redshifts. We use both HST NICMOS and ground-based adaptive-optics imaging to study the morphologies of galaxies we have identified as having old stellar populations from photometric data.
At z ~ 1.5, we find that a substantial fraction of our sample comprises spheroids similar to elliptical galaxies at the present epoch, but there are also some galaxies dominated by disks of old stars.  At z ~ 2.5, we have so far found no normal spheroids, and disks appear to be dominant.  Some of the consequences of these results will be briefly discussed.