Primordial Black Holes - Perspectives in Gravitational Wave Astronomy -

TL;DR

This review explores the role of primordial black holes in gravitational wave astronomy, discussing their formation, observational constraints, and potential detection methods through gravitational waves, highlighting the field's future prospects.

Contribution

It provides a comprehensive overview of PBHs in the context of gravitational wave observations, integrating formation theories, constraints, and detection strategies, which is a novel synthesis in this area.

Findings

Gravitational wave detection offers a new observational window for PBHs.

Various inflation models can produce PBHs with different mass spectra.

Future gravitational wave observations could significantly constrain PBH abundance.

Abstract

This is a review article on the primordial black holes (PBHs), with particular focus on the massive ones ($\gtrsim 10^{15}{\rm g}$) which have not evaporated by the present epoch by the Hawking radiation. By the detections of gravitational waves by LIGO, we have gained a completely novel tool to observationally search for PBHs complementary to the electromagnetic waves. Based on the perspective that gravitational-wave astronomy will make a significant progress in the next decades, a purpose of this article is to give a comprehensive review covering a wide range of topics on PBHs. After discussing PBH formation as well as several inflation models leading to PBH production, we summarize various existing and future observational constraints. We then present topics on formation of PBH binaries, gravitational waves from PBH binaries, various observational tests of PBHs by using gravitational waves.