The influence of mergers and ram-pressure stripping on black hole-bulge correlations

TL;DR

This paper investigates the factors influencing the correlation between supermassive black hole mass and galaxy bulge mass, finding that mergers alone cannot explain the observed scatter and suggesting a role for active galactic nucleus feedback and ram-pressure stripping.

Contribution

It introduces an analysis showing that SMBH-bulge correlations are affected by feedback mechanisms and environmental effects, beyond simple merger models.

Findings

Scatter increases faster than merger-only predictions.

Active galactic nucleus feedback likely influences SMBH-bulge relation.

Ram-pressure stripping may cause missing stellar mass in cluster galaxies.

Abstract

We analyse the scatter in the correlation between super-massive black hole (SMBH) mass and bulge stellar mass of the host galaxy, and infer that it cannot be accounted for by mergers alone. The merger-only scenario, where small galaxies merge to establish a proportionality relation between the SMBH and bulge masses, leads to a scatter around the linear proportionality line that increases with the square root of the SMBH (or bulge) mass. By examining a sample of 103 galaxies we find that the intrinsic scatter increases more rapidly than expected from the merger-only scenario. The correlation between SMBH masses and their host galaxy properties is therefore more likely to be determined by a negative feedback mechanism that is driven by an active galactic nucleus. We find a hint that some galaxies with missing stellar mass reside close to the centre of clusters and speculate that ram-pressure stripping of gas off the young galaxy as it moves near the cluster centre, might explain the missing stellar mass at later times.