An empirical approach to selecting the first growing black hole seeds with JWST/NIRCam

TL;DR

This paper proposes a color selection method using JWST/NIRCam to identify early low-mass black hole seeds at high redshift, aiding in understanding black hole formation and growth.

Contribution

It introduces a new 3-band, 2-color selection technique with high completeness and purity to detect growing black hole seeds at z~7-10.

Findings

Achieves 90% completeness and purity in selecting black hole candidates.

Effectively separates active black holes from inactive galaxies in color space.

Demonstrates the method's applicability to JWST/NIRCam observations.

Abstract

The James Webb Space Telescope (JWST) will have the sensitivity to detect early low-mass black holes as they transition from "seeds" to supermassive black holes (BHs). Based on the JAGUAR mock catalog of galaxies, we present a clean color selection that takes advantage of the unique UV slope of accreting supermassive black holes with relatively low mass and high accretion rates. We show for a range of host stellar masses that those galaxies hosting $\sim 10^{6} M_{\odot}$ BHs radiating at >10% of their Eddington luminosity separate in color space from inactive systems. Here we propose a set of 3-band, 2-color selection boxes (with 90% completeness; 90% purity; balanced purity/completeness) with JWST/NIRCam to identify the most promising growing BH candidates at $z \sim 7-10$.