Clustering dependence on Ly<i>α</i> luminosity from MUSE surveys at 3 &lt; <i>z</i> &lt; 6

Abstract

We investigate the dependence of Ly α emitter (LAE) clustering on Ly α luminosity and connect the clustering properties of ≈ L ⋆ LAEs with those of much fainter ones, namely, ≈0.04 L ⋆ . We use 1030 LAEs from the MUSE-Wide survey, 679 LAEs from MUSE-Deep, and 367 LAEs from the to-date deepest ever spectroscopic survey, the MUSE Extremely Deep Field. All objects have spectroscopic redshifts of 3 &lt; z &lt; 6 and cover a large dynamic range of Ly α luminosities: 40.15 &lt; log( L Ly α /erg s −1 ) &lt; 43.35. We apply the Adelberger et al. K-estimator as the clustering statistic and fit the measurements with state-of-the-art halo occupation distribution (HOD) models. We find that the large-scale bias factor increases weakly with an increasing line luminosity. For the low-luminosity (log⟨ L Ly α /[erg s −1 ]⟩ = 41.22) and intermediate-luminosity (log⟨ L Ly α /[erg s −1 ]⟩ = 41.64) LAEs, we compute consistent bias factors b low = 2.43 −0.15 +0.15 and b interm. = 2.42 −0.09 +0.10 , whereas for the high-luminosity (log⟨ L Ly α /[erg s −1 ]⟩ = 42.34) LAEs we calculated b high = 2.65 −0.11 +0.13 . Consequently, high-luminosity LAEs occupy dark matter halos (DMHs) with typical masses of log( M h /[ h −1 M ⊙ ]) = 11.09 −0.09 +0.10 , while low-luminosity LAEs reside in halos of log( M h /[ h −1 M ⊙ ]) = 10.77 −0.15 +0.13 . The minimum masses to host one central LAE, M min , and (on average) one satellite LAE, M 1 , also vary with Ly α luminosity, growing from log( M min /[ h −1 M ⊙ ]) = 10.3 −0.3 +0.2 and log( M 1 /[ h −1 M ⊙ ]) = 11.7 −0.2 +0.3 to log( M min /[ h −1 M ⊙ ]) = 10.7 −0.3 +0.2 and log( M 1 /[ h −1 M ⊙ ]) = 12.4 −0.6 +0.4 from low- to high-luminosity samples, respectively. The satellite fractions are ≲10% (≲20%) at 1 σ (3 σ ) confidence level, supporting a scenario in which DMHs typically host one single LAE. We next bisected the three main samples into disjoint subsets to thoroughly explore the dependence of the clustering properties on L Ly α . We report a strong (8 σ ) clustering dependence on Ly α luminosity, not accounting for cosmic variance effects, where the highest luminosity LAE subsample (log( L Ly α /erg s −1 ) ≈ 42.53) clusters more strongly ( b highest = 3.13 −0.15 +0.08 ) and resides in more massive DMHs (log( M h /[ h −1 M ⊙ ] )= 11.43 −0.10 +0.04 ) than the lowest luminosity one (log( L Ly α /erg s −1 ) ≈ 40.97), which presents a bias of b lowest = 1.79 −0.06 +0.08 and occupies log( M h /[ h −1 M ⊙ ]) = 10.00 −0.09 +0.12 halos. We discuss the implications of these results for evolving Ly α luminosity functions, halo mass dependent Ly α escape fractions, and incomplete reionization signatures.

Topics & Concepts