Multi-wavelength detectability of isolated black holes in the Milky Way

TL;DR

This paper evaluates the potential for detecting isolated black holes in the Milky Way through multi-wavelength observations, considering accretion physics, astrophysical uncertainties, and future radio telescope capabilities.

Contribution

It provides a comprehensive model for the detectability of isolated black holes in radio and X-ray bands, incorporating recent accretion physics and simulations.

Findings

Estimated the number of observable black holes in different Galactic regions.

Assessed the impact of astrophysical uncertainties on detection predictions.

Evaluated SKA's potential to detect accreting black holes in the Galaxy.

Abstract

Isolated black holes in our Galaxy have eluded detection so far. We present here a comprehensive study on the detectability of isolated stellar-mass astrophysical black holes that accrete interstellar gas from molecular clouds in both the local region and the Central Molecular Zone. We adopt a state-of-the-art model for the accretion physics backed up by numerical simulations, and study the number of observable sources in both the radio and X-ray band, as a function of a variety of parameters. We discuss in particular the impact of the astrophysical uncertainties on our prediction for the number of bright X-ray sources in the central region of the Galaxy. We finally consider future developments in the radio domain, and assess the potential of SKA to detect a population of astrophysical black holes accreting gas in our Galaxy.