The Sloan Digital Sky Survey Reverberation Mapping Project : quasar host galaxies at z <0.8 from image decomposition

Abstract

We present the rest-frame UV and optical photometry and morphology of low-redshift broad-line quasar host galaxies from the Sloan Digital Sky Survey Reverberation Mapping project. Our sample consists of 103 quasars at z < 0.8, spanning a luminosity range of -25 <= Mg <= -17 mag. We stack the multi-epoch images in the g and i bands taken by the Canada-France-Hawaii Telescope. The combined g-band (i-band) images reach a 5σ depth of 26.2 (25.2) mag, with a typical PSF size of 0 ''.7 (0 ''.6). Each quasar is decomposed into a PSF and a Sérsic profile, representing the central AGN and the host galaxy components, respectively. The systematic errors of the measured host galaxy flux in the two bands are 0.23 and 0.18 mag. The relative errors of the measured galaxy half-light radii (Re) are about 13%. We estimate the rest-frame u- and g-band flux of the host galaxies, and find that the AGN-to-galaxy flux ratios in the g band are between 0.9 to 4.4 (68.3% confidence). These galaxies have high stellar masses M* = 1010-1011M(circle dot). They have similar color with star-forming galaxies at similar redshifts, in consistent with AGN positive feedback in these quasars. We find that the M*–MBH relation in our sample is shallower than the local MBulge-MBH relation. The Sérsic indices and the M*-Re relation indicate that the majority of the host galaxies are disk-like.