Primordial Black Hole formation from overlapping cosmological fluctuations

Abstract

We consider the formation of primordial black holes (PBHs), during the radiation-dominated Universe, generated from the collapse of super-horizon curvature fluctuations that are overlapped with others on larger scales. Using a set of different curvature profiles, we show that the threshold for PBH formation (defined as the critical peak of the compaction function) can be decreased by several percentages, thanks to the overlapping between two peaks in the profile of the compaction function. In the opposite case, when the fluctuations are sufficiently decoupled the threshold values behave as having the fluctuations isolated (isolated peaks). We find that the analytical estimates of arXiv:1907.13311 can be used accurately when applied to the corresponding peak that is leading to the gravitational collapse. We also study in detail the dynamics and estimate the final PBH mass for different initial configurations, showing that the profile dependence has a significant effect on that.

28 pages and 17 figures. v3: figures and discussions improved. Accepted for publication in JCAP

References in corpus (5)

• Primordial Black Holes as Dark Matter
• The Threshold for Primordial Black Hole Formation: a Simple Analytic Prescription
• Curvature profiles as initial conditions for primordial black hole formation
• Self-consistent initial conditions for primordial black hole formation
• The double formation of primordial black holes

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• Inflationary relics from an Ultra-Slow-Roll plateau
• The impact of the eccentricity on the collapse of an ellipsoid into a black hole
• Aspects of Spatially-Correlated Random Fields: Extreme-Value Statistics and Clustering Properties
• Effect of stochastic kicks on primordial black hole abundance and mass via the compaction function