A Search for Moderate-Redshift Survivors from the Population of Luminous
  Compact Passive Galaxies at High Redshift
  From a search of a ~ 2400 square degree region covered by both the SDSS and
UKIDSS databases, we have attempted to identify galaxies at z ~ 0.5 that are
consistent with their being essentially unmodified examples of the luminous
passive compact galaxies found at z ~ 2.5. After isolating good candidates via
deeper imaging, we further refine the sample with Keck moderate-resolution
spectroscopy and laser-guide-star adaptive-optics imaging. For 4 of the 5
galaxies that so far remain after passing through this sieve, we analyze
plausible star-formation histories based on our spectra in order to identify
galaxies that may have survived with little modification from the population
formed at high redshift. We find 2 galaxies that are consistent with having
formed > 95% of their mass at z > 5. We attempt to estimate masses both from
our stellar population determinations and from velocity dispersions. Given the
high frequency of small axial ratios, both in our small sample and among
samples found at high redshifts, we tentatively suggest that some of the more
extreme examples of passive compact galaxies may have prolate morphologies.
