Intergalactic Lyman-$\alpha$ haloes before reionization are detectable with JWST

TL;DR

This paper predicts that JWST can detect intergalactic Lyman-alpha haloes before reionization, providing insights into neutral hydrogen during cosmic reionization through observational forecasts and data-driven constraints.

Contribution

It offers the first detailed forecast of JWST's capability to detect Lyman-alpha haloes during reionization, based on observed UV luminosities and a data-driven approach.

Findings

Individual haloes with luminosity > 10^{43} ergs/s detectable at z < 9

Stacking ~10 haloes enables detection up to z ~ 16

Detection of haloes informs on neutral hydrogen during reionization

Abstract

The $James \ Webb \ Space \ Telescope \ (JWST)$ recently reported a large population of UV luminous galaxies at high redshifts, $ z > 10$, as well as Lyman-$\alpha$ emitting (LAE) galaxies out to $z \sim 11$. We use the observed UV luminosities along with a data-driven approach at lower redshifts to place constraints on the observability of the intergalactic Lyman-$\alpha$ intensity, scattered in the form of Loeb-Rybicki haloes, during the pre-reionization and reionization epochs ($z \sim 9-16$). We forecast the sensitivity and resolution required to detect these intergalactic haloes, finding that individual haloes with LAE luminosities $> 10^{43}$ ergs/s are detectable at a few sigma level at $z \lesssim 9$, while stacking of $\sim 10$ haloes is expected to result in detections out to $z \sim 16$. Finding these haloes is expected to shed light on the neutral intergalactic hydrogen during cosmic reionization.