2015ApJ...799..164P

We investigate the cosmic evolution of the black hole (BH) mass-bulge luminosity relation using a sample of 52 active galaxies at z ∼ 0.36 and z ∼ 0.57 in the BH mass range of 10^7.4-10^9.1 M_☉. By consistently applying multicomponent spectral and structural decomposition to high-quality Keck spectra and high-resolution Hubble Space Telescope images, BH masses (M_BH) are estimated using the Hβ broad emission line combined with the 5100 Å nuclear luminosity, and bulge luminosities (L_bul) are derived from surface photometry. Comparing the resulting M_BH- L_bul relation to local active galaxies and taking into account selection effects, we find evolution of the form M_BH/L_bul∝(1 + z)^γ with γ = 1.8±0.7, consistent with BH growth preceding that of the host galaxies. Including an additional sample of 27 active galaxies with 0.5 < z < 1.9 taken from the literature and measured in a consistent way, we obtain γ = 0.9±0.7 for the M_BH- L_bulrelation and γ = 0.4±0.5 for the M_BH-total host galaxy luminosity (L_host) relation. The results strengthen the findings from our previous studies and provide additional evidence for host galaxy bulge growth being dominated by disk-to-bulge transformation via minor mergers and/or disk instabilities.