A correlation between central supermassive black holes and the globular cluster systems of early-type galaxies

TL;DR

This study reveals a tight power-law correlation between the mass of central supermassive black holes and the number of globular clusters in early-type galaxies, suggesting the SMBH mass is approximately equal to the total globular cluster mass.

Contribution

It introduces a new, more accurate predictor for SMBH mass based on globular cluster counts, outperforming the traditional M_BH-sigma relation.

Findings

SMBH mass correlates strongly with globular cluster number

The relation has a small scatter of 0.2 dex

Galaxies with high globular cluster frequency have more massive SMBHs

Abstract

Elliptical, lenticular, and early-type spiral galaxies show a remarkably tight power-law correlation between the mass M_BH of their central supermassive black hole (SMBH) and the number N_GC of globular clusters: M_BH=m*N_GC^(1.08+/-0.04) with m=1.7*10^5 solar masses. Thus, to a good approximation the SMBH mass is the same as the total mass of the globular clusters. Based on a limited sample of 13 galaxies, this relation appears to be a better predictor of SMBH mass (rms scatter 0.2 dex) than the M_BH-sigma relation between SMBH mass and velocity dispersion sigma. The small scatter reflects the fact that galaxies with high globular cluster specific frequency S_N tend to harbor SMBHs that are more massive than expected from the M_BH-sigma relation.