Clustering dependence on Lyα luminosity from MUSE surveys at 3 < z < 6

¹ Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
e-mail: yherreroalonso@aip.de
² Universidad Nacional Autónoma de México, Instituto de Astronomía (IA-UNAM-E), AP 106, Ensenada, 22860 BC, Mexico
³ Leiden Observatory, Leiden University, PO Box 9513 2300 RA Leiden, The Netherlands
⁴ Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zurich, Switzerland
⁵ Observatoire de Genève, Université de Genève, 51 Chemin de Pégase, 1290 Versoix, Switzerland

Received: 5 August 2022
Accepted: 23 December 2022

Abstract

We investigate the dependence of Lyα emitter (LAE) clustering on Lyα luminosity and connect the clustering properties of ≈L^⋆ LAEs with those of much fainter ones, namely, ≈0.04L^⋆. 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 < z < 6 and cover a large dynamic range of Lyα luminosities: 40.15 < log(L_Lyα/erg s⁻¹) < 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_Lyα/[erg s⁻¹]⟩ = 41.22) and intermediate-luminosity (log⟨L_Lyα/[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_Lyα/[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, M₁, also vary with Lyα luminosity, growing from log(M_min/[h⁻¹M_⊙]) = 10.3_−0.3^+0.2 and log(M₁/[h⁻¹ M_⊙]) = 11.7_−0.2^+0.3 to log(M_min/[h⁻¹ M_⊙]) = 10.7_−0.3^+0.2 and log(M₁/[h⁻¹ M_⊙]) = 12.4_−0.6^+0.4 from low- to high-luminosity samples, respectively. The satellite fractions are ≲10% (≲20%) at 1σ (3σ) 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_Lyα. We report a strong (8σ) clustering dependence on Lyα luminosity, not accounting for cosmic variance effects, where the highest luminosity LAE subsample (log(L_Lyα/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⁻¹M_⊙] )= 11.43_−0.10^+0.04) than the lowest luminosity one (log(L_Lyα/erg s⁻¹) ≈ 40.97), which presents a bias of b_lowest = 1.79_−0.06^+0.08 and occupies log(M_h/[h⁻¹M_⊙]) = 10.00_−0.09^+0.12 halos. We discuss the implications of these results for evolving Lyα luminosity functions, halo mass dependent Lyα escape fractions, and incomplete reionization signatures.