Near-infrared imaging of low-redshift quasar host galaxies. II. High-luminosity quasars

We present H-band images of a complete sample of 26 high-luminosity quasars selected from the Bright Quasar Survey. We detect the quasar host galaxy in at least 23 of these objects. We compare these galaxies with host galaxies from a complementary sample of low-luminosity quasars and find the hosts of the high-luminosity quasars to be significantly brighter at H and possibly more massive. The average galaxy magnitude corresponds to a luminosity (and approximate mass) twice that of an L* galaxy. The high-luminosity quasars are possibly more likely to have brighter interacting companions than their low-luminosity counterparts. These results are consistent with suggestions that the highest levels of activity in radio-quiet quasars require a large host galaxy or a close interaction with a massive galaxy and that some of these interactions result in mergers. We also present what we believe is the first published infrared image of the jet of 3C 273, and we compare this image to optical and radio images from the literature. The results are consistent with suggestions that the knots at the end of the jet are due to rapid energy loss where the jet is burrowing into the surrounding medium.