Determine the strength and scale of the galaxy–Lyα transmission peak

Determine the exact strength of the peak in the galaxy–Lyα forest cross-correlation function around reionisation-era line-emitting galaxies and the distance at which the peak occurs across observational surveys.

Background

The paper reviews observations of the Lyα forest near high-redshift [O III] emitters and notes that the surveys broadly agree on enhanced transmission near galaxies, but do not agree precisely on the amplitude or radial location of the signal. The discrepancy may arise from cosmic variance, different galaxy-selection methods, and differing survey resolutions.

Resolving the peak strength and scale is important for quantifying how strongly galaxies modify the surrounding ionising background and for comparing observational measurements with reionisation simulations.

References

However, the exact strength of the peak in the cross-correlation function and the distance at which it occurs among the different surveys are still somewhat uncertain, complicated by a combination of cosmic variance, differing galaxy detection methods and varying survey resolutions.

— Exploring the influence of reionisation-era galaxies on their local intergalactic medium using the Sherwood-Relics simulations  (2609.26483 - Anderson et al., 22 Sep 2026) in Section 1, Introduction

The relative roles of galaxies and AGN in setting the amplitude and scale of the cross-correlation also remain uncertain \citep{Jin2026}.

— Exploring the influence of reionisation-era galaxies on their local intergalactic medium using the Sherwood-Relics simulations  (2609.26483 - Anderson et al., 22 Sep 2026) in Section 1, Introduction

The statistical significance of these trends remains uncertain, reflecting the observational limits of current ground-based surveys \citep{Meyer2020}.

— Exploring the influence of reionisation-era galaxies on their local intergalactic medium using the Sherwood-Relics simulations  (2609.26483 - Anderson et al., 22 Sep 2026) in Section 1, Introduction