Do Intermediate-Mass Black Holes Exist in Globular Clusters?

TL;DR

This paper investigates the existence of intermediate-mass black holes in globular clusters, highlighting discrepancies between observational constraints and models, and suggesting outflows in accretion flows as a possible explanation.

Contribution

It proposes that outflows in accretion flows could reconcile radio observation limits with dynamical models for IMBHs in GCs.

Findings

Current radio observations cannot definitively rule out IMBHs in GCs.

Outflows in accretion flows may explain the discrepancy between observations and models.

Revisiting the IMBH hypothesis using the 7;M-L_{R} relation supports previous findings.

Abstract

The existence of intermediate-mass black holes (IMBHs) in globular clusters (GCs) remains a crucial problem. Searching IMBHs in GCs reveals a discrepancy between radio observations and dynamical modelings: the upper mass limits constrained by radio observations are systematically lower than that of dynamical modelings. One possibility for such a discrepancy is that, as we suggest in this work, there exist outflows in accretion flows. Our results indicate that, for most sources, current radio observations cannot rule out the possibility that IMBHs may exist in GCs. In addition, we adopt an \dot{M}-L_{R} relation to revisit this issue, which confirms the results obtained by the Fundamental Plane relation.