New models of nonsingular black hole dark matter from limiting curvature

TL;DR

This paper introduces phenomenological models of nonsingular black holes with limiting curvature, exploring their astrophysical implications and effects on primordial black hole dark matter properties.

Contribution

It proposes new models of nonsingular black holes with regulators larger than the horizon scale and analyzes their impact on black hole thermodynamics and dark matter constraints.

Findings

Regulator scale influences black hole mass ranges and thermodynamics.

Models with de Sitter and Minkowski cores show observable effects.

Constraints on primordial black hole dark matter are affected by these models.

Abstract

We consider phenomenological models for nonsingular black holes that satisfy the limiting curvature condition (i.e., that have curvatures that are always sub-Planckian in size) while having a more general dependence on the black hole mass than the most studied examples. These models allow black holes to exist while having regulators that are larger than the horizon scale; it has been shown previously that this can lead to observable consequences in an astrophysical setting, for allowed choices for the regulator scale. Noting that substantial horizon-scale modifications of the metric will affect black hole thermodynamics and Hawking radiation, we study these metrics in the context of primordial black hole dark matter. Considering examples with de\,Sitter and Minkowski cores, respectively, we study the effect of the regulator in these metrics on the allowed black hole mass ranges (or ``bands"), the black hole temperature, specific heat and lifetime, and the bounds on the primordial black hole fraction of the total dark matter density from the observed extragalactic gamma ray background.