Black Hole - Galaxy Scaling Relationships for Active Galactic Nuclei with Reverberation Masses

TL;DR

This study uses high-resolution imaging to analyze the relationships between black hole masses and host galaxy properties in active galactic nuclei, confirming known correlations and providing insights into their predictive power and scaling trends.

Contribution

It presents a detailed analysis of black hole-host galaxy scaling relations using reverberation-mapped masses and high-resolution imaging, improving understanding of these correlations in active galaxies.

Findings

MBH-Lbulge has the least scatter, making it the best predictor of MBH.

MBH-Mstars shows a clear trend with black hole mass, unlike MBH-Lgalaxy.

The observed scaling relations agree with dynamical models and Illustris simulations.

Abstract

We have utilized high-resolution optical Hubble Space Telescope images and deep, ground-based near-infrared images to examine the host-galaxies of 37 active galactic nuclei with reverberation-based black hole masses. Using two-dimensional image decompositions, we have separated the host galaxy from the bright central AGN, allowing a re-examination of the MBH-Lbulge and MBH-Lgalaxy relationships and the MBH-Mbulge and MBH-Mstars relationships using V-H color to constrain the stellar mass-to-light ratio. We find clear correlations for all of these scaling relationships, and the best-fit correlations are generally in good agreement with the sample of early-type galaxies with MBH from dynamical modeling and the sample of megamasers. We also find good agreement with the expectations from the Illustris simulations, although the agreement with other simulations is less clear because of the different black hole mass ranges that are probed. MBH-Lbulge is found to have the least scatter, and is therefore the best predictor of MBH among the relationships examined here. Large photometric surveys that rely on automated analysis and forego bulge-to-disk decompositions will achieve more accurate MBH predictions if they rely on MBH-Mstars rather than MBH-Lgalaxy. Finally, we have examined MBH/Mstars and find a clear trend with black hole mass but not galaxy mass. This same trend is also exhibited by galaxies with MBH from dynamical modeling and megamaser galaxies, as well as simulated galaxies from Illustris, rising from ~0.01% at 10^6 Msun to ~1.0% at 10^10 Msun. This scaling should be taken into account when comparing galaxy samples that are not matched in MBH.