Feeding plankton to whales: high-redshift supermassive black holes from tiny black hole explosions

TL;DR

This paper proposes that tiny primordial black holes can heat early universe gas clouds, preventing molecular cooling and enabling the direct formation of supermassive black holes at high redshifts.

Contribution

It introduces a novel mechanism where primordial black holes facilitate early SMBH formation by heating gas clouds and suppressing fragmentation.

Findings

Primordial black holes can heat gas clouds to prevent molecular hydrogen formation.

Heating by black holes enables direct collapse of gas into SMBHs at high redshift.

This mechanism explains the early appearance of supermassive black holes.

Abstract

Recent observations of the high-redshift universe have uncovered a significant number of active galactic nuclei, implying that supermassive black holes (SMBHs) would have to have been formed at much earlier times than expected. Direct collapse of metal-free gas clouds to SMBHs after recombination could help explain the early formation of SMBHs, but this scenario is stymied by the fragmentation of the clouds due to efficient molecular hydrogen cooling. We show that a subdominant population of tiny, evaporating primordial black holes, with significant clustering in some gas clouds, can heat the gas sufficiently so that molecular hydrogen is not formed, and direct collapse to to black holes is possible even at high redshifts.