2019/03/12 by Nandini Sahu, Alister W. Graham, Benjamin L. Davis · 1 citation
Physics and Astronomy · #astro-ph.GA
paper · pdf · doi:10.3847/1538-4357/ab0f32
published as ApJ, 876, 155 (2019) · 73 pages, 53 figures, and 5 tables, accepted for publication by the Astrophysical Journal (11 March 2019)
arxiv created 2019/03/12 · arxiv updated 2019/05/29
Analyzing a sample of 84 early-type galaxies with directly-measured super-massive black hole masses---nearly doubling the sample size of such galaxies with multi-component decompositions---a symmetric linear regression on the reduced (merger-free) sample of 76 galaxies reveals MBH∝ M*,sph1.27± 0.07 with a total scatter of Δrms= 0.52 dex in the log(MBH) direction. However, and importantly, 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*,gal1.8± 0.2 and Δrms=0.6± 0.1 dex depending on the sample. For MBH \gtrsim 107 M\odot, 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-Sérsic versus Sérsic, early-type galaxies. For reference, the ensemble of late-type galaxies (which invariably are Sérsic galaxies) follow MBH-M*,sph and MBH-M*,gal relations with slopes equal to 2.16± 0.32 and 3.05± 0.70, respectively. Finally, we provide some useful conversion coefficients, υ, 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.