NEAR-INFRARED OBSERVATIONS OF EXTENDED EMISSION AROUND PG-1545+210

Infrared images at H and Ks of the quasar PG 1545+210 clearly show bot h extended emission centered on the quasar and a companion galaxy. The magnitudes of the extended emission deduced from these observations d epend strongly on the model adopted for the emission. Both an exponent ial disk model and a de Vaucouleurs model provide adequate fits to the extended emission. If it is assumed to follow an exponential disk gal axy, these measurements imply that the host galaxy has absolute magnit udes comparable with those of a Schechter L galaxy. With this assumpt ion for the intrinsic light distribution, the H magnitude and the Hubb le Space Telescope limit on the V magnitude are inconsistent with colo r predictions for unreddened spiral galaxies at the redshift of the qu asar. If the data are fitted to a de Vaucouleurs model, the extended e mission dominates the total energy of the system and significantly exc eeds that of an L galaxy. The companion galaxy has colors consistent with its being at the redshift of the quasar, but its luminosity is at most a small part of that of the entire system. If the companion is a t the redshift of PG 1545+210, its absolute magnitude is M(H) similar to-22 mag, significantly fainter than that of an L galaxy.