Near-infrared AO imaging of QSO host galaxies

We report NIR (primarily H-band) AO imaging with the Gemini-N and Subaru telescopes, of 32 nearby (z < 0.3) QSOs selected from the Palomar-Green bright quasar survey (PGBQS), in order to investigate the properties of the host galaxies. Two-dimensional modeling and visual inspection of the images shows that ∼36% of the hosts are ellipticals, ∼39% contain a prominent disk component, and ∼25% are of undetermined type. Thirty percent show obvious signs of disturbance. The mean M_H(host) = -24.82 (2.1 L_H^*), with a range -23.5 to -26.5. At < L_H^*, all hosts have a dominant disk component, while at > 2 L_H^* most are ellipticals. "Disturbed" hosts are found at all M_H(host). Hosts with prominent disks have less luminous QSOs, while the most luminous QSOs are almost exclusively in ellipticals or in mergers (which presumably shortly will be ellipticals). There is a strong correlation between the "infrared-excess", L_IR/L_BB, of QSOs with host type and degree of disturbance. Disturbed and strongly disturbed hosts and hosts with dominant disks have L_IR/L_BB twice that of non-disturbed and elliptical hosts, respectively.