Primordial black holes: constraints, potential evidence and prospects

TL;DR

This review discusses primordial black holes as dark matter candidates, summarizing observational constraints, potential evidence, formation scenarios, and future detection prospects with gravitational-wave observatories.

Contribution

It provides a comprehensive overview of current constraints, possible evidence, and future prospects for primordial black holes across all mass ranges.

Findings

Current observational constraints limit PBH abundance in various mass ranges.

Potential gravitational-wave signals may indicate PBH existence.

Different formation scenarios predict distinct PBH mass functions.

Abstract

Primordial black holes (PBHs) may have formed in the early Universe and may account for all or part of the dark matter. In this review, we summarize the current observational constraints on PBHs across the full mass range, highlight potential evidence for their existence, and outline the prospects for future searches, particularly with gravitational-wave observatories. We also discuss different PBH formation scenarios, identify the corresponding mass functions, and present the observational constraints in each case.