Non-Gaussian Formation of Primordial Black Holes: Effects on the Threshold

Jun 17, 2019
28 pages
Published in:
  • JCAP 12 (2019) 029
  • Published: Dec 10, 2019
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Abstract: (IOP)
Primordial black holes could have been formed in the early universe from sufficiently large cosmological perturbations re-entering the horizon when the Universe is still radiation dominated. These originate from the spectrum of curvature perturbations generated during inflation at small-scales. Because of the non-linear relation between the curvature perturbation ζζ and the overdensity δρδρ, the formation of the primordial black holes is affected by intrinsic non-Gaussianity even if the curvature perturbation is Gaussian. We investigate the impact of this non-Gaussianity on the critical threshold δcδ_c which measures the excess of mass of the perturbation, finding a relative change with respect to the value obtained using a linear relation between ζζ and δρδρ, of a few percent suggesting that the value of the critical threshold is rather robust against non-linearities. The same holds also when local primordial non-Gaussianity, with fNL>3/2f_{NL}{_{\sim}^{>}} −3/2, are added to the curvature perturbation.
Note:
  • 24 pages, 6 figures. This last updated version contains minor fine-tunings according to the published one
  • curvature: perturbation
  • black hole: primordial
  • non-Gaussianity
  • formation
  • mass: perturbation
  • black hole: formation
  • inflation
  • effect: nonlinear
  • horizon