The Fundamental Plane Evolution of Active Galactic Nucleus Host Galaxies

Abstract

We measured the stellar velocity dispersions of 15 active galactic nucleus (AGN) host galaxies at redshifts as high as $\sim 0.34$. Combining these with published velocity dispersion measurements from the literature, we study the Fundamental Plane of AGN host galaxies and its evolution. BL Lac hosts and radio galaxies seem to lie on the same Fundamental Plane as normal early-type galaxies. The evolution of the mass-to-light ratio of AGN host galaxies shows a similar trend to that observed in normal early-type galaxies, consistent with single-burst passive evolution models with formation redshifts $z \gtrsim 1$. The lack of a significant difference between normal and AGN host galaxies in the Fundamental plane supports the &#34;Grand Unification&#34; picture wherein AGNs are a transient phase in the evolution of normal galaxies. The black hole masses of BL Lac objects and radio galaxies, derived using the mass -- dispersion relation, are similar. The black hole mass is independent of BL Lac type. The local black hole mass -- host galaxy luminosity relation of our sub-sample at $z < 0.1$ is similar to that of local normal and radio galaxies, but is less well defined at higher redshift due to the luminosity evolution of the host galaxies.