Black Hole Mass Scaling Relations for Early-type Galaxies. I. M _BH-M _{∗, sph} and M _BH-M _∗,gal

Analyzing a sample of 84 early-type galaxies (ETGs) with directly measured supermassive black hole masses-nearly doubling the sample size of such galaxies with multicomponent decompositions-a symmetric linear regression on the reduced (merger-free) sample of 76 galaxies reveals MBH ∝ M1.27 ±;0.07_∗,sph with a total scatter of Δ_rms = 0.52 dex in the log(MBH) direction. Importantly, however, we discover that the ES/S0-type galaxies with disks are offset from the E-type galaxies by more than a factor of ten in their MBH/M_∗,sph ratio, with ramifications for formation theories, simulations, and some virial factor measurements used to convert AGN virial masses into MBH. Separately, each population follows a steeper relation with slopes of 1.86 ±; 0.20 and 1.90 ±; 0.20, respectively. The offset mass ratio is mainly due to the exclusion of the disk mass, with the two populations offset by only a factor of two in their MBH/M_∗,gal ratio in the MBH-M_∗,gal diagram where MBH ∝ M_∗,gal 1.8±; 0.2and Δ_rms = 0.6 ±; 0.1 dex depending on the sample. For MBH ≳10⁷M_o, we detect no significant bend nor offset in either the MBH-M_∗,sph or MBH-M_∗,gal relations due to barred versus non-barred, or core-Sersic versus Sersic, ETGs. For reference, the ensemble of late-type galaxies (which invariably are Sersic galaxies) follow MBH-M_∗,sph and MBH-M_∗,gall relations with slopes equal to 2.16±;0.32 and 3.05±;00.70, respectively. Finally, we provide some useful conversion coefficients, ν, accounting for the different stellar mass-to-light ratios used in the literature, and we report the discovery of a local, compact massive spheroid in NGC 5252.