Constraining intermediate-mass black holes from the stellar disc of SgrA*

TL;DR

This paper uses the observed stellar disc around SgrA* and kinetic theory to constrain the presence of intermediate-mass black holes, showing their potential to disrupt the disc through vector resonant relaxation.

Contribution

It provides a quantitative analysis of how intermediate-mass black holes would affect the stellar disc's stability around SgrA* using kinetic predictions and recent observations.

Findings

Intermediate-mass black holes can significantly disrupt the stellar disc.

Constraints on the number and mass of black holes near SgrA*.

The stellar disc's survival limits the population of intermediate-mass black holes.

Abstract

Stars evolving around a supermassive black hole see their orbital orientations diffuse efficiently, a process called "vector resonant relaxation". In particular, stars within the same disc, i.e. neighbors in orientations, will slowly diffuse away from one another through this stochastic process. We use jointly (i) detailed kinetic predictions for the efficiency of this dilution and (ii) the recent observation of a stellar disc around SgrA*, the supermassive black hole at the centre of the Milky-Way, to constrain SgrA*'s unobserved stellar cluster. Notably, we investigate quantitatively the impact of a population of intermediate mass black holes on the survivability of the stellar disc.