Primordial black holes confront LIGO/Virgo data: current situation
By V. D. Luca, G. Franciolini, P. Pani, A. Riotto. Journal of Cosmology and Astroparticle Physics, 2020
173 citations recorded by the source corpus.
The LIGO and Virgo Interferometers have so far provided 11 gravitational-wave (GW) observations of black-hole binaries. Similar detections are bound to become very frequent in the near future. With the current and upcoming wealth of data, it is possible to confront specific formation models with observations. We investigate here whether current data are compatible with the hypothesis that LIGO/Virgo black holes are of primordial origin. We compute in detail the mass and spin distributions of primordial black holes (PBHs), their merger rates, the stochastic background of unresolved coalescences, and confront them with current data from the first two observational runs, also including the recently discovered GW190412. We compute the best-fit values for the parameters of the PBH mass distribution at formation that are compatible with current GW data. In all cases, the maximum fraction of PBHs in dark matter is constrained by these observations to be f PBH≈ few× 10−3. We discuss the predictions of the PBH scenario that can be directly tested as new data become available. In the most likely formation scenarios where PBHs are born with negligible spin, the fact that at least one of the components of GW190412 is moderately spinning is incompatible with a primordial origin for this event, unless accretion or hierarchical mergers are significant. In the absence of accretion, current non-GW constraints already exclude that LIGO/Virgo events are all of primordial origin, whereas in the presence of accretion the GW bounds on the PBH abundance are the most stringent ones in the relevant mass range. A strong phase of accretion during the cosmic history would favour mass ratios close to unity, and a redshift-dependent correlation between high masses, high spins and nearly-equal mass binaries, with the secondary component spinning faster than the primary. Finally, we highlight that accretion can play an important role to relax current constraints on the PBH abundance, which calls for a better modelling of the mass and angular momentum accretion rates at redshift 0z≲3.
Subfields: Astronomy and Astrophysics
View Paper: https://www.semanticscholar.org/paper/b2d9ad08193018369b6fd980579705c58001a00e
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Citations in the corpus
- Two populations of LIGO-Virgo black holes (2020, methodology): “[22, 33], the different accretion scenarios for PBHs were parametrized by a cut-off redshift zcut−off below which accretion contributes negligibly to the evolution of the binary.”
- Primordial black holes as dark matter candidates (2021, background): “The effects of accretion could also be important [174].”
- Rates of compact object coalescences (2021, background): “…black holes, merger rate predictions are sensitive assumptions about the initial distribution of such sources in binaries or small clusters (e.g., Ali-Häımoud et al., 2017; Korol et al., 2020; De Luca et al., 2020a) as well as possible accretion onto primordial black holes (De Luca et al., 2020b).”