Poster Presentation

Properties of quasar host galaxies at z < 1 revealed by Subaru HSC

Author(s): Toru Ishino, Yuya Saeda, Yoshiki Matsuoka

Presenter: Toru Ishino (Ehime University)

It is well known that there is a tight correlation between the mass of supermassive black holes ( SMBHs ) and mass of their host bulges, suggesting that they coevolve. As a driver of the coevolution, AGN feedback was proposed, which suppresses star formation activity within their host galaxies. However, the actual impact of AGNs on their host galaxies is still unclear. To understand this, it is important to investigate the properties of AGN host galaxies accurately. One way to do so is to decompose quasar images into nucleus and host galaxies, which requires deep optical images with good spatial resolution.
In this study, we used Subaru Hyper Suprime-Cam ( HSC ) SSP survey images, which are a suitable dataset for this analysis. We investigated the host properties of about 750 quasars at z < 1, extracted from the SDSS DR7 quasar catalog. We fitted the observed radial profiles with a combination of the point spread function and the Sersic model to decompose into quasar nuclei and host galaxy in the g, r, i, z, and y bands. The properties of the host galaxies were then derived through the SED fitting. By comparing the properties of the quasar hosts and normal galaxies without AGN, we found that quasar host galaxies are mostly located on the green valley, between the distributions of blue-cloud and red-sequence galaxies. This trend suggests that AGN activity may be responsible for a transition of galaxies from blue cloud to red sequence.