Titans of the Early Universe: The Prato Statement on the Origin of the First Supermassive Black Holes

TL;DR

This paper reviews current theories and observational evidence on the formation of supermassive black holes in the early universe, emphasizing the role of massive seed black holes from supermassive star collapse.

Contribution

It synthesizes recent progress and open questions regarding the formation, evolution, and observational prospects of primordial supermassive black holes.

Findings

Massive seeds from supermassive star collapse are viable progenitors.

Observational evidence supports early formation of supermassive black holes.

Many questions remain about formation frequency and evolution mechanisms.

Abstract

In recent years, the discovery of massive quasars at z~7 has provided a striking challenge to our understanding of the origin and growth of supermassive black holes in the early Universe. Mounting observational and theoretical evidence indicates the viability of massive seeds, formed by the collapse of supermassive stars, as a progenitor model for such early, massive accreting black holes. Although considerable progress has been made in our theoretical understanding, many questions remain regarding how (and how often) such objects may form, how they live and die, and how next generation observatories may yield new insight into the origin of these primordial titans. This review focusses on our present understanding of this remarkable formation scenario, based on discussions held at the Monash Prato Centre from November 20--24, 2017, during the workshop "Titans of the Early Universe: The Origin of the First Supermassive Black Holes."