The hosts of ultraluminous infrared galaxies

Complete samples of ultraluminous infrared galaxies (ULIGs(1)) have been imaged at R-band and It-band from Mauna Kea. Here we present a preliminary analysis of the host galaxy magnitudes and the 1-D radial profiles for a subset of objects in the IRAS 1-Jy sample of ULIGs (z < 0.3), and compare these properties with recently published data for "low-z" QSOs. ULIGs in the 1-Jy sample reside in luminous hosts, with mean luminosities N 2.7 L-K* (Delta(K) similar to 0.7-11 L-K*), and similar to 2.2 L-R* (Delta(R) similar to 0.5-9 L-R*), values which are remarkably similar in the mean and range for the hosts of low-z QSOs. Approximately one-third of ULIGs have single nuclei and radial profiles that are closely approximated by a r(1/4)-law over the inner similar to 2-10 kpc radius. These "E-like" hosts have half-light radii, and surface brightness (r(1/2), mu(1/2)) Similar to QSO hosts at R-band, but systematically smaller half-light radii than QSOs at K-band.