# Constraining primordial black hole masses with the isotropic gamma ray background

## TL;DR

This paper extends constraints on primordial black hole masses using the isotropic gamma ray background, considering extended mass functions and Kerr black holes, closing part of the mass window for near-extremal black holes.

## Contribution

It introduces an analysis of extended mass functions and Kerr black holes to refine constraints on primordial black holes from gamma ray observations.

## Key findings

- Lower mass window can be closed for near-extremal Kerr black holes.
- Constraints are extended to a broader mass range $10^{13}-10^{18}\,g$.
- Black hole evaporation limits are consistent with observed gamma ray background.

## Abstract

Primordial black holes can represent all or most of the dark matter in the window $10^{17}-10^{22}\,$g. Here we present an extension of the constraints on PBHs of masses $10^{13}-10^{18}\,$g arising from the isotropic diffuse gamma ray background. Primordial black holes evaporate by emitting Hawking radiation that should not exceed the observed background. Generalizing from monochromatic distributions of Schwarzschild black holes to extended mass functions of Kerr rotating black holes, we show that the lower part of this mass window can be closed for near-extremal black holes.