Far Infrared Loud Quasars 1: Disturbed and Quiescent Quasars in the PG Survey

We use host galaxy imaging studies of the PG Quasar survey to compare the farinfrared (FIR) properties of quasars with disturbed and undisturbed host galaxies. By using survival analysis, we show that the quasars with disturbed host galaxies, with morphologies classified from a homogenous data set, have a 60μm luminosity distribution that is different from that of those with undisturbed hosts with >97% confidence. For morphological classifications using an inhomogenous data set, including HST data for some objects, this confidence rises to >99% confidence. The mean 60μm luminosity of the disturbed–host quasars is several times greater than that of the undisturbed-host quasars. However, possible biases in the PG survey might affect these conclusions. Our results are interpreted as supporting the idea that quasars are related to at least some Ultraluminous Infrared Galaxies. We discuss the implications of this result for studies of quasar and galaxy evolution.