Hearing the birth of the lightest intermediate mass black holes with the second generation gravitational wave detectors

TL;DR

This paper explores the potential for second-generation gravitational wave detectors to detect the birth of the lightest intermediate mass black holes, which are crucial for understanding black hole evolution, and finds promising prospects for near-future observations.

Contribution

It assesses the likelihood of detecting the formation of LIMBHs via gravitational waves with advanced detectors, highlighting the importance of merger-driven scenarios over silent collapse.

Findings

Detection probability of LIMBH birth is higher than pre-merger identification.

Second-generation detectors could observe LIMBH formation in upcoming runs.

Adding more detectors increases detection rates.

Abstract

Intermediate mass black holes (IMBHs) with a mass between $10^{2}$ and $10^{5}$ times that of the sun, which bridges the {mass gap between the} stellar-mass black holes and the supermassive black holes, are crucial in understanding the evolution of the black holes. Although they are widely believed to exist, decisive evidence has long been absent. Motivated by the successful detection of massive stellar-mass black holes by advanced LIGO, through the gravitational wave radiation during the binary merger, in this work we investigate the prospect of detecting/identifying the lightest IMBHs (LIMBHs; the black holes $\gtrsim 100M_\odot$) with the second generation gravitational wave detectors. In general, the chance of hearing the birth of the LIMBHs is significantly higher than that to identify pre-merger IMBHs. The other formation channel of LIMBHs, where stars with huge mass/low-metallicity directly collapse, is likely "silent", so the merger-driven birth of the LIMBHs may be the only "observable" scenario in the near future. Moreover, the prospect of establishing the presence of (lightest) intermediate mass black holes in the O3 run and beyond of advanced LIGO is found quite promising, implying that such an instrument could make another breakthrough on astronomy in the near future. The joining of other detectors like advanced Virgo would only increase the detection rate.