MOCCA-SURVEY Database I: Is NGC 6535 a Dark Star Cluster Harboring an IMBH?

TL;DR

This study models dark star clusters dominated by intermediate-mass black holes and suggests that NGC 6535 may harbor such an IMBH, based on simulated observations matching real data.

Contribution

The paper introduces a new class of dark star cluster models with IMBHs and demonstrates their observational properties using simulations and mock observations.

Findings

NGC 6535's properties match the dark star cluster model

Potential presence of an IMBH in NGC 6535

IMBH detection feasible with kinematic observations

Abstract

We describe the dynamical evolution of a unique type of dark star cluster model in which the majority of the cluster mass at Hubble time is dominated by an intermediate-mass black hole (IMBH). We analyzed results from about 2000 star cluster models (Survey Database I) simulated using the Monte-Carlo code MOCCA and identified these dark star cluster models. Taking one of these models, we apply the method of simulating realistic "mock observations" by utilizing the COCOA and SISCO codes to obtain the photometric and kinematic observational properties of the dark star cluster model at 12 Gyr. We find that the perplexing Galactic globular cluster NGC 6535 closely matches the observational photometric and kinematic properties of the dark star cluster model presented in this paper. Based on our analysis and currently observed properties of NGC 6535, we suggest that this globular cluster could potentially harbour an IMBH. If it exists, the presence of this IMBH can be detected robustly with proposed kinematic observations of NGC 6535.