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

We analyse the scatter in the correlation between supermassive black hole (SMBH) mass andbulge 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 relationbetween the SMBH and bulge masses, leads to a scatter around the linear proportionality linethat increases with the square root of the SMBH (or bulge) mass. By examining a sample of103 galaxies, we find that the intrinsic scatter increases more rapidly than expected from themerger-only scenario. The correlation between SMBH masses and their host galaxy propertiesis therefore more likely to be determined by a negative feedback mechanism that is driven byan active galactic nucleus. We find, a hint, that some galaxies with missing stellar mass resideclose to the centre of clusters and speculate that ram-pressure stripping of gas off the younggalaxy as it moves near the cluster centre, might explain the missing stellar mass at later times.