Connecting CGM enrichment with Lyman alpha emitters at 2.9 < z < 6.7

TL;DR

This study uses VLT/MUSE data to identify Lyman alpha emitters at high redshift and explores their relationship with metal absorbers in the circumgalactic medium, revealing insights into galaxy-CGM interactions.

Contribution

It presents the first comprehensive connection between high-redshift LAEs and CGM metal absorbers, highlighting the distribution and properties of low-mass galaxies influencing the CGM.

Findings

Detected 156 LAEs at 2.9<z<6.7 with luminosities log L=41.3-43.2.

Found 34 C IV and 14 Mg II absorbers associated with LAEs within 250 pkpc.

Low ionisation gas shows a lower covering fraction around LAEs.

Abstract

We present the results of a blind search for Lyman $\alpha$ emitters (LAEs) in three deep archival $z\sim6$ quasar fields from VLT/MUSE using state-of-the-art detection algorithms. We explore their connection with absorbers-particularly C IV and Mg II-in the circumgalactic medium (CGM) from the E-XQR-30 survey. We detect 156 LAEs at $2.9<z<6.7$ with luminosities ranging from log $L[\text{ergs}^{-1}]=$ 41.3 to 43.2. We find 34 and 14 galaxy associations with C IV and Mg II absorption respectively at $3.4<z<5.8$ within a line of sight velocity window of $\pm1000~\text{km}^{-1}$ and impact parameter of $<250$ pkpc. These systems have a weak anti-correlation with respect to the absorber strength-impact parameter relation. No Mg II systems are found within the virial radii of any LAE while four C IV absorbers are located within the virial radii of an LAE suggesting that low ionisation gas has a lower covering fraction. The LAEs have mild overdensity ratios of 1.7 and 1.9 around C IV and Mg II respectively. The stellar mass upper limits of $\text{log}~M_*<10.7~\text{M}_\odot$ estimated using Keck/NIRC2 imaging indicate that a low-mass, faint population of galaxies pollutes the CGM with metals. This paper serves as a pilot analysis for the forthcoming REQUIEM survey, an ESO Large Program on high redshift deep quasar fields.