Observational signatures of massive black hole formation in the early universe

TL;DR

This paper explores how space telescope observations can identify early massive black hole formation through unique emission signatures, aiding understanding of supermassive black hole origins in the universe's first billion years.

Contribution

It introduces diagnostic predictions for detecting direct-collapse black holes at high redshift using JWST, based on simulation of their unique emission features and star formation effects.

Findings

Distinct colors and emission lines depend on star formation and black hole accretion rates.

JWST can potentially detect direct-collapse black holes at redshift 15 with minimal exposure.

Massive seed black holes emit strong Lyman-Werner radiation that dissociates H$_2$.

Abstract

Space telescope observations of massive black holes during their formation may be key to understanding the origin of supermassive black holes and high-redshift quasars. To create diagnostics for their detection and confirmation, we study a simulation of a nascent massive, so-called direct-collapse, black hole that induces a wave of nearby massive metal-free star formation, unique to this seeding scenario and to very high redshifts. Here we describe a series of distinct colors and emission line strengths, dependent on the relative strength of star formation and black hole accretion. We predict that the forthcoming James Webb Space Telescope might be able to detect and distinguish a young galaxy that hosts a direct-collapse black hole in this configuration at redshift 15 with as little as a 20,000-second total exposure time across four filters, critical for constraining supermassive black hole seeding mechanisms and early growth rates. We also find that a massive seed black hole produces strong, H$_2$-dissociating Lyman-Werner radiation.