The Cosmic Evolution of Quasar Hosts

Abstract

Ground based and HST imaging of quasars (see, e.g., Dunlop et al. 2003; Pagani et al. 2003 and references therein) clearly indicate that at z < 0.5 quasars are hosted in massive galaxies dominated by the spheroidal component. While radio loud quasars (RLQ) are exclusively hosted by ellipticals exceeding by 2–3 mag L*, radio quiet quasars (RQQ) are found both in ellipticals and in spirals. On the other hand there is mounting evidence that most if not all nearby massive spheroids have inactive supermassive BH in their centers (see e.g. Ferrarese 2002 for a review). Taken together these findings depict a scenario where nuclear activity may be a common phenomenon during the lifetime of a galaxy. Understanding how the properties of the galaxies hosting quasars change with the cosmic time is therefore a fundamental step to investigate the link between the evolution of the galaxies and the nuclear activity.

Keywords

These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.