Primordial black hole compaction function from stochastic fluctuations in ultra-slow-roll inflation

Fuente: arXiv
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Autori principali: Raatikainen, Sami, Rasanen, Syksy, Tomberg, Eemeli
Natura: Preprint
Pubblicazione: 2023
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author Raatikainen, Sami
Rasanen, Syksy
Tomberg, Eemeli
author_facet Raatikainen, Sami
Rasanen, Syksy
Tomberg, Eemeli
contents We study the formation of primordial black holes (PBH) with ultra-slow-roll inflation when stochastic effects are important. We use the $ΔN$ formalism and simplify the stochastic equations with an analytical constant-roll approximation. Considering a viable inflation model, we find the spatial profile of the PBH compaction function numerically for each stochastic patch, without assumptions about Gaussianity or the radial profile. The stochastic effects that lead to an exponential tail for the density distribution also make the compaction function very spiky, unlike assumed in the literature. Naively using collapse thresholds found for smooth profiles, the PBH abundance is enhanced by up to a factor of $10^9$, and the PBH mass distribution is spread over three orders of magnitude in mass. The results point to a need to redo numerical simulations of PBH formation with spiky profiles.
format Preprint
id arxiv_https___arxiv_org_abs_2312_12911
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Primordial black hole compaction function from stochastic fluctuations in ultra-slow-roll inflation
Raatikainen, Sami
Rasanen, Syksy
Tomberg, Eemeli
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
We study the formation of primordial black holes (PBH) with ultra-slow-roll inflation when stochastic effects are important. We use the $ΔN$ formalism and simplify the stochastic equations with an analytical constant-roll approximation. Considering a viable inflation model, we find the spatial profile of the PBH compaction function numerically for each stochastic patch, without assumptions about Gaussianity or the radial profile. The stochastic effects that lead to an exponential tail for the density distribution also make the compaction function very spiky, unlike assumed in the literature. Naively using collapse thresholds found for smooth profiles, the PBH abundance is enhanced by up to a factor of $10^9$, and the PBH mass distribution is spread over three orders of magnitude in mass. The results point to a need to redo numerical simulations of PBH formation with spiky profiles.
title Primordial black hole compaction function from stochastic fluctuations in ultra-slow-roll inflation
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2312.12911