The MUSE-Wide survey: Three-dimensional clustering analysis of Lyman-α emitters at 3.3 < z < 6

Abstract

We present an analysis of the spatial clustering of 695 Lyα-emitting galaxies (LAEs) in the MUSE-Wide survey. All objects have spectroscopically confirmed redshifts in the range 3.3 < z < 6. We employed the K-estimator, an alternative clustering statistic, adapted and optimized for our sample. We also explore the standard two-point correlation function approach, which is however less suited for a pencil-beam survey such as ours. The results from both approaches are consistent. We parametrize the clustering properties in two ways, (i) following the standard approach of modelling the clustering signal with a power law (PL), and (ii) adopting a halo occupation distribution (HOD) model of the two-halo term. Using the K-estimator and applying HOD modelling, we infer a large-scale bias of bHOD = 2.80−0.38+0.38 at a median redshift of the number of galaxy pairs ⟨zpair⟩ ≃ 3.82, while the best-fit power-law analysis gives bPL = 3.03−0.52+1.51 (r0 = 3.60−0.90+3.10 comoving h−1 Mpc and γ = 1.30−0.45+0.36). The implied typical dark matter halo (DMH) mass is log(MDMH/[h−1 M⊙]) = 11.34−0.27+0.23 (adopting b = bHOD and assuming σ8 = 0.8). We study possible dependencies of the clustering signal on object properties by bisecting the sample into disjoint subsets, considering Lyα luminosity, UV absolute magnitude, Lyα equivalent width, and redshift as variables. We find no evidence for a strong dependence on the latter three variables but detect a suggestive trend of more luminous Lyα emitters clustering more strongly (thus residing in more massive DMHs) than their lower Lyα luminosity counterparts. We also compare our results to mock LAE catalogs based on a semi-analytic model of galaxy formation and find a stronger clustering signal than in our observed sample, driven by spikes in the simulated z-distributions. By adopting a galaxy-conserving model we estimate that the Lyα-bright galaxies in the MUSE-Wide survey will typically evolve into galaxies hosted by halos of log(MDMH/[h−1 M⊙]) ≈ 13.5 at redshift zero, suggesting that we observe the ancestors of present-day galaxy groups.