Black hole and nuclear cluster scaling relations: M_bh ~ M_nc^{2.7+/-0.7}

TL;DR

This paper derives a new scaling relation between black hole mass and nuclear star cluster mass, revealing a steep power-law relation that enhances understanding of their co-evolution within host galaxies.

Contribution

It introduces a novel M_bh ~ M_nc^{2.7} relation based on combining existing scaling laws, improving insights into black hole and star cluster growth.

Findings

Derived M_bh ~ M_nc^{2--3.4} relation from observed correlations.

The relation supports rapid black hole growth in dense star clusters.

Consistent with quadratic M_bh-M_sph relation in Sersic spheroids.

Abstract

There is a growing array of supermassive black hole and nuclear star cluster scaling relations with their host spheroid, including a bent (black hole mass)-(host spheroid mass) M_bh-M_sph relation and different (massive compact object mass)-(host spheroid velocity dispersion) M_mco-sigma relations for black holes and nuclear star clusters. By combining the observed M_bh ~ sigma^(5.5) relation with the observed M_nc ~ sigma^(1.6--2.7) relation, we derive the expression M_bh ~ (M_nc)^(2--3.4), which should hold until the nuclear star clusters are eventually destroyed in the larger core-Sersic spheroids. This new mass scaling relation helps better quantify the rapid evolutionary growth of massive black holes in dense star clusters, and the relation is consistently recovered when coupling the observed M_nc ~ (M_sph)^(0.6--1.0) relation with the recently observed quadratic relation M_bh ~ (M_sph)^2 for Sersic spheroids.