Ultralow mass primordial black holes in the early Universe can explain the pulsar timing array signal

Bhaumik, N and Jain, RK and Lewicki, M (2023) Ultralow mass primordial black holes in the early Universe can explain the pulsar timing array signal. In: Physical Review D, 108 (12).

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Abstract

Pulsar timing array collaborations have recently announced the discovery of a stochastic gravitational wave (GW) background at nanohertz frequencies. We analyze the GW signals from the domination of ultralow mass primordial black holes (PBHs) in the early Universe and show that they can explain this recent discovery. This scenario requires a relatively broad peak in the power spectrum of scalar perturbations from inflation with a spectral index in a narrow range of 1.45-1.6. The resulting PBH population would have mass around 108 g, and the initial abundance βf lies between 10-10 and 10-9. We find that this explanation is preferred by the data over the generic model, assuming supermassive black holes as the source. These very light PBHs would decay before big bang nucleosynthesis; however, upcoming third-generation terrestrial laser interferometers would be able to test the model by observing the GW spectrum produced during the formation of the PBHs. Also, the scalar power spectra associated with our scenario will be within the reach of PIXIE probing cosmic microwave background spectral distortions. © 2023 American Physical Society.

Item Type:	Journal Article
Publication:	Physical Review D
Publisher:	American Physical Society
Additional Information:	The copyright for this article belongs to the publisher.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	02 Aug 2024 11:52
Last Modified:	02 Aug 2024 11:52
URI:	http://eprints.iisc.ac.in/id/eprint/85303

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