No Significant Evolution of Relations between Black Hole Mass and Galaxy Total Stellar Mass Up to z ∼ 2.5

Abstract

We investigate the cosmic evolution of the ratio between black hole (BH) mass (M<SUB>BH</SUB>) and host galaxy total stellar mass (M<SUB>stellar</SUB>) out to z ∼ 2.5 for a sample of 100 X-ray-selected moderate-luminosity, broad-line active galactic nuclei (AGNs) in the Chandra-COSMOS Legacy Survey. By taking advantage of the deep multiwavelength photometry and spectroscopy in the COSMOS field, we measure in a uniform way the galaxy total stellar mass using an spectral energy distribution decomposition technique and the BH mass based on broad emission line measurements and single-epoch virial estimates. Our sample of AGN host galaxies has total stellar masses of 10<SUP>10-12</SUP>M<SUB>⊙</SUB>, and BH masses of 10<SUP>7.0-9.5</SUP>M<SUB>⊙</SUB>. Combining our sample with the relatively bright AGN samples from the literature, we find no significant evolution of the M<SUB>BH</SUB>-M<SUB>stellar</SUB> relation with the BH-to-host total stellar mass ratio of M<SUB>BH</SUB>/M<SUB>stellar</SUB> ∼ 0.3% at all redshifts probed. We conclude that the average BH-to-host stellar mass ratio appears to be consistent with the local value within the uncertainties, suggesting a lack of evolution of the M<SUB>BH</SUB>-M<SUB>stellar</SUB> relation up to z ∼ 2.5.