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Main Authors: Kasai, Kentaro, Kawasaki, Masahiro, Murai, Kai, Neda, Shunsuke
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2604.19316
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author Kasai, Kentaro
Kawasaki, Masahiro
Murai, Kai
Neda, Shunsuke
author_facet Kasai, Kentaro
Kawasaki, Masahiro
Murai, Kai
Neda, Shunsuke
contents Primordial black holes (PBHs) may form an initially clustered population depending on their production mechanism. Motivated by binary black-hole merger events observed by gravitational-wave interferometers, we revisit the evaluation of the merger rate of PBH binaries and extend the formalism to include the effects of clustering. We show that, in the presence of relatively weak PBH clustering, the LIGO-Virgo-KAGRA events can be explained with a smaller value of $f_{\mathrm{PBH}}$ than in scenarios with Poisson-distributed PBHs, at least in the early two-body channel. However, for stronger clustering, the merger rate in the two-body channel is significantly suppressed due to the formation of three-body systems.
format Preprint
id arxiv_https___arxiv_org_abs_2604_19316
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Merger rate of initially clustered primordial black holes for the two-body channel
Kasai, Kentaro
Kawasaki, Masahiro
Murai, Kai
Neda, Shunsuke
Cosmology and Nongalactic Astrophysics
Primordial black holes (PBHs) may form an initially clustered population depending on their production mechanism. Motivated by binary black-hole merger events observed by gravitational-wave interferometers, we revisit the evaluation of the merger rate of PBH binaries and extend the formalism to include the effects of clustering. We show that, in the presence of relatively weak PBH clustering, the LIGO-Virgo-KAGRA events can be explained with a smaller value of $f_{\mathrm{PBH}}$ than in scenarios with Poisson-distributed PBHs, at least in the early two-body channel. However, for stronger clustering, the merger rate in the two-body channel is significantly suppressed due to the formation of three-body systems.
title Merger rate of initially clustered primordial black holes for the two-body channel
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2604.19316