Signatures of primordial black holes in gravitational wave clustering

Sarah Libanore, Michele Liguori, Alvise Raccanelli

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


The possible existence of primordial black holes (PBHs) is an open question in modern cosmology. Among the probes to test it, gravitational waves (GW) coming from their mergers constitute a powerful tool. In this work, we study how stellar mass PBH binaries could affect measurements of the clustering of merger events in future GW surveys. We account for PBH binaries formed both in the early and late Universe and show that the power spectrum modification they introduce can be detected at ∼ 2σ-3σ (depending on some assumptions) whenever PBH mergers make up at least ∼ 60% of the overall number of detected events. By adding cross-correlations with galaxy surveys, this threshold is lowered to ∼ 40%. In the case of a poor redshift determination of GW sources, constraints are degraded by about a factor of 2. Assuming a theoretical model for the PBH merger rate, we can convert our results to constraints on the fraction of dark matter in PBHs, f PBH. Finally, we perform a Bayesian model selection forecast and confirm that the analysis we develop could be able to detect ∼30 M PBHs if they account for f PBH ∼ 10-4 - 10-3, depending on the model uncertainty considered, being thus competitive with other probes.

Original languageEnglish
Article number055
JournalJournal of Cosmology and Astroparticle Physics
Issue number8
StatePublished - 1 Aug 2023


  • cosmological parameters from LSS
  • gravitational waves / sources
  • primordial black holes
  • redshift surveys

ASJC Scopus subject areas

  • Astronomy and Astrophysics


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