The first sample of ultraluminous infrared galaxies at high redshift. I. Sample and near-infrared morphologies

We present a new sample of distant ultraluminous infrared galaxies. The sam ple was selected from a positional cross-correlation of the IRAS Faint Sour ce Catalog with the FIRST database. Objects from this set were selected for spectroscopy by virtue of following the well-known star-forming galaxy cor relation between 1.4 GHz and 60 mum flux, and by being optically faint on t he POSS. Optical identification and spectroscopy were obtained for 108 targ ets at the Lick Observatory 3 m telescope. Most objects show spectra typica l of starburst galaxies and do not show the high-ionization lines of active galactic nuclei. The redshift distribution covers 0.1 < z < 0.9, with 13 o bjects at z > 0.5 and an average redshift of (z) over bar = 0.31. K-band im ages were obtained at the IRTF, Lick, and Reck observatories in sub-arcsec seeing of all optically identified targets. About two-thirds of the objects appear to be interacting galaxies, while the other one-third appear to be normal. Nearly all the identified objects have far-IR luminosities greater than 10(11) L., and similar to 25% have L-FIR > 10(12) L..