M - sigma relation between SMBHs and the velocity dispersion of globular cluster systems

TL;DR

This study reveals a strong correlation between supermassive black hole mass and the velocity dispersion of red globular clusters, extending the known MBH - sigma_sph relation to include globular cluster systems.

Contribution

It introduces the MBH - sigma_GC relation, linking black hole mass to globular cluster velocity dispersion, especially focusing on red clusters, with a tight correlation and low scatter.

Findings

MBH correlates with sigma_GC in host galaxies.

Red globular clusters' velocity dispersion yields a tight MBH relation.

The relation allows black hole mass estimates in galaxies.

Abstract

We find evidence that the mass MBH of central supermassive black holes (SMBHs) correlates with the velocity dispersion sigma_GC of globular cluster systems of their host galaxies. This extends the well-known MBH - sigma_sph relation between black hole mass and velocity dispersion of the host spheroidal component. We compile published measurements of both MBH and sigma_GC for a sample of 13 systems and find the relation log(MBH) = alpha + beta log(sigma_GC/200) with alpha = 8.63 \pm 0.09 and beta = 3.76 \pm 0.52. We also consider blue (metal-poor) and red (metal-rich) globular clusters sub-populations separately and obtain a surprisingly tight correlation using only the velocity dispersion sigma_GC^red of the red clusters with alpha = 8.73 \pm 0.09 and beta = 3.84 \pm 0.52 and an intrinsic scatter eps_0 = 0.22 dex compared to eps_0 = 0.27 dex for the MBH - sigma_sph of our sample. We use our MBH - sigma_GC relation to estimate the central black hole mass in five galaxies for which sigma_GC^red is measured.