Global Stellar Budget for LIGO Black Holes

Abstract

The binary black hole mergers observed by LIGO-Virgo gravitational-wave detectors pose two major challenges: (i) how to produce these massive black holes from stellar processes; and (ii) how to bring them close enough to merge within the age of the universe? We derive a fundamental constraint relating the binary separation and the available stellar budget in the universe to produce the observed black hole mergers. We find that $\lesssim 14\%$ of the entire budget contributes to the observed merger rate of $(30+30){\mathrm{M}}_{\odot }$ black holes, if the separation is around the diameter of their progenitor stars. Furthermore, the upgraded LIGO detector and third-generation gravitational-wave detectors are not expected to find stellar-mass black hole mergers at high redshifts. From LIGO's strong constraints on the mergers of black holes in the pair-instability mass-gap ($60-120{\mathrm{M}}_{\odot }$), we find that $\lesssim 0.8\%$ of all massive stars contribute to a remnant black hole population in this gap. Our derived separation$-$budget constraint provides a robust framework for testing the formation scenarios of stellar binary black holes.

References in corpus (6)

• Advanced Virgo: a 2nd generation interferometric gravitational wave detector
• Cosmic Star Formation History
• Binary interaction dominates the evolution of massive stars
• Pulsational Pair-Instability Supernovae
• Very massive stars, pair-instability supernovae and intermediate-mass black holes with the SEVN code
• Merging black holes in young star clusters

Cited by in corpus (2)

• Properties and astrophysical implications of the 150 Msun binary black hole merger GW190521
• Formation of mass gap objects in highly asymmetric mergers