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arXiv · 2105.03349

Searching for a subpopulation of primordial black holes in LIGO/Virgo gravitational-wave data

Gabriele Franciolini·Vishal Baibhav·Valerio De Luca·Ken K. Y. Ng·Kaze W. K. Wong·Emanuele Berti·Paolo Pani·Antonio Riotto·Salvatore Vitale
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Abstract

With several dozen binary black hole events detected by LIGO/Virgo to date and many more expected in the next few years, gravitational-wave astronomy is shifting from individual-event analyses to population studies. Using the GWTC-2 catalog, we perform a hierarchical Bayesian analysis that for the first time combines several state-of-the-art astrophysical formation models with a population of primordial black holes (PBHs) and constrains the fraction of a putative subpopulation of PBHs in the data. We find that this fraction depends significantly on the set of assumed astrophysical models. While a primordial population is statistically favored against certain competitive astrophysical channels, such as globular clusters and nuclear stellar clusters, a dominant contribution from the stable-mass-transfer isolated formation channel drastically reduces the need for PBHs, except for explaining the rate of mass-gap events like GW190521. The tantalizing possibility that black holes formed after inflation are contributing to LIGO/Virgo observations could only be verified by further reducing uncertainties in astrophysical and primordial formation models, and it may ultimately be confirmed by third-generation interferometers.

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Gabriele Franciolini, Vishal Baibhav, Valerio De Luca, Ken K. Y. Ng, Kaze W. K. Wong, Emanuele Berti, Paolo Pani, Antonio Riotto, Salvatore Vitale. 2021-05-07. Searching for a subpopulation of primordial black holes in LIGO/Virgo gravitational-wave data. https://doi.org/10.1103/physrevd.105.083526

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