Cosmological constraints on primordial black holes produced in the near-critical gravitational collapse

Abstract

The mass function of primordial black holes created through the near-critical gravitational collapse is calculated in a manner fairly independent of the statistical distribution of underlying density fluctuation, assuming that it has a sharp peak on a specific scale. Comparing it with various cosmological constraints on their mass spectrum, some newly excluded range is found in the volume fraction of the region collapsing into black holes as a function of the horizon mass.

Figures (2)

• Figure 1: Expected mass function of PBHs (\ref{['delomega']}) created through the near-critical gravitational collapse in the case density fluctuation has a sharp peak on the mass scale $M_H$.
• Figure 2: Cosmological constraints on the volume fraction of the region, $\beta$, above the threshold of PBH formation when the horizon mass is equal to $M_H$. The region between the solid and the dotted lines is newly excluded.