Relation Between Globular Clusters and Supermassive Black Holes in Ellipticals as a Manifestation of the Black Hole Fundamental Plane

TL;DR

This study explores the correlation between supermassive black hole mass and globular cluster count in elliptical galaxies, suggesting the relation is an indirect consequence of the black hole fundamental plane and bulge properties.

Contribution

It demonstrates that the tight Mbh-Ngc correlation arises from mutual dependence on stellar mass and bulge binding energy, not a direct causal link.

Findings

The Mbh-Ngc relation has small scatter due to shared residual correlation with stellar mass.

The correlation is consistent with feedback-regulated models emphasizing bulge binding energy.

Globular clusters trace elliptical galaxy formation, linking to the black hole fundamental plane.

Abstract

We analyze the relation between the mass of the central supermassive black hole (Mbh) and the number of globular clusters (Ngc) in elliptical galaxies and bulges as a ramification of the black hole fundamental plane, the theoretically predicted and observed multi-variable correlation between Mbh and bulge binding energy. Although the tightness of the Mbh-Ngc correlation suggests an unlikely causal link between supermassive black holes and globular clusters, such a correspondence can exhibit small scatter even if the physical relationship is indirect. We show that the relatively small scatter of the Mbh-Ngc relation owes to the mutual residual correlation of Mbh and Ngc with stellar mass when the velocity dispersion is held fixed. Thus, present observations lend evidence for feedback-regulated models in which the bulge binding energy is most important; they do not necessarily imply any `special' connection between globular clusters and Mbh. This raises the question of why Ngc traces the formation of ellipticals and bulges sufficiently well to be correlated with binding energy.