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arXiv · 1910.09580

Global Stellar Budget for LIGO Black Holes

Karan Jani·Abraham Loeb
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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.

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BibTeXRIS

Karan Jani, Abraham Loeb. 2019-10-21. Global Stellar Budget for LIGO Black Holes. https://doi.org/10.3847/2041-8213%2Fab6854

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