Host Galaxies of Quasars in Hyper Suprime-Cam:Single, Dual, and Fading

Abstract

Strong correlations between the mass of supermassive black holes and the properties of their host galaxies suggest an evolutionary connection between the two. It is difficult to study the host galaxies of quasars to explore this connection due to their extreme luminosities. Only recently have telescopes advanced enough to begin to make out details in these galaxies' structures. Variable quasars that have faded over time by a significant amount may have host galaxies that are easier to observe. In this paper, we analyze the decomposed HSC images of 661 ($0 < z < 1.1$) quasars, 331 of which have faded by over 0.5 mag between SDSS DR14 and HSC PDR3. The other 330 were divided into two control groups. We measure host galaxy magnitudes along with other properties through this two-dimensional model fitting. By comparing properties of host galaxies of faded quasars to those of our two control groups, we were able to systematically analyze differences in properties of host galaxies of faded quasars. We determined that host galaxies of faded quasars are disproportionately either going through mergers or have recently undergone a merger. Host galaxies of faded quasars are detectably more luminous as well, making them ideal candidates for future observations.