The MUSE-Wide survey: A measurement of the Ly$\alpha$ emitting fraction among $z>3$ galaxies

TL;DR

This study measures the fraction of Lyman alpha emitters among high-redshift galaxies using MUSE data, finding a high and consistent fraction across redshifts 3 to 6, with no dependence on UV luminosity or redshift.

Contribution

First large-scale measurement of Lyα emitter fraction at z>3 using MUSE, revealing a high and stable fraction across different redshifts and luminosities.

Findings

Lyα emitter fraction is ≥50% across 3<z<6.

29% of Lyα emitters have rest-EWs ≤ 15Å.

No dependence of Lyα fraction on redshift or UV luminosity.

Abstract

We present a measurement of the fraction of Lyman $\alpha$ (Ly$\alpha$) emitters ($X_{\rm{Ly} \alpha}$) amongst HST continuum-selected galaxies at $3<z<6$ with the Multi-Unit Spectroscopic Explorer (MUSE) on the VLT. Making use of the first 24 MUSE-Wide pointings in GOODS-South, each having an integration time of 1 hour, we detect 100 Ly$\alpha$ emitters and find $X_{\rm{Ly} \alpha}\gtrsim0.5$ for most of the redshift range covered, with 29 per cent of the Ly$\alpha$ sample exhibiting rest equivalent widths (rest-EWs) $\leq$ 15\AA. Adopting a range of rest-EW cuts (0 - 75\AA), we find no evidence of a dependence of $X_{\rm{Ly} \alpha}$ on either redshift or UV luminosity.