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Recent detections of extended Lyman-α halos around Lyα emitters (LAEs) have been reported on a regular basis, but their origin is still under investigation. Simulation studies predict that the outer regions of the extended halos contain a major contribution from the Lyα emission of faint, individually undetected LAEs. To address this matter from an observational angle, we used halo occupation distribution (HOD) modeling to reproduce the clustering of a spectroscopic sample of 1265 LAEs at 3 < z < 5 from the MUSE-Wide survey. We integrated the Lyα luminosity function to estimate the background surface brightness due to discrete faint LAEs. We then extended the HOD statistics inwards towards small separations and computed the factor by which the measured Lyα surface brightness is enhanced by undetected close physical neighbors. We considered various clustering scenarios for the undetected sources and compared the corresponding radial profiles. This enhancement factor from LAE clustering depends strongly on the spectral bandwidth Δv over which the Lyα emission is integrated and this value can amount to ≈20 − 40 for small values of Δv (around 200 − 400 km s−1) as achieved by recent studies utilizing integral-field spectrographic data. The resulting inferred Lyα surface brightness of faint LAEs ranges between (0.4 − 2)×1020 erg s−1 cm−2 arcsec−2, with a very slow radial decline outwards. Our results suggest that the outer regions of observed Lyα halos (R ≳ 50 pkpc) could indeed contain a strong component from external (but physically associated) LAEs, and may even be dominated by them. It is only for a relatively shallow faint-end slope of the Lyα luminosity function that this contribution from clustered LAEs would be rendered insignificant. We also confirm that the observed emission from the inner regions (R ≤ 20 − 30 pkpc) is too bright to be substantially affected by clustering. We compare our findings with predicted profiles from simulations and find good overall agreement. We outline possible future measurements to further constrain the impact of discrete undetected LAEs on observed extended Lyα halos. [ABSTRACT FROM AUTHOR]

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(LLyα/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⟨LLyα/[erg s−1]⟩ = 41.22) and intermediate-luminosity (log⟨LLyα/[erg s−1]⟩ = 41.64) LAEs, we compute consistent bias factors blow = 2.43−0.15+0.15 b low = 2. 43 − 0.15 + 0.15 $ b_\mathrm{{low}}=2.43^{+0.15}_{-0.15} $ and binterm. = 2.42−0.09+0.10 b interm. = 2. 42 − 0.09 + 0.10 $ b_\mathrm{{interm.}}=2.42^{+0.10}_{-0.09} $ , whereas for the high-luminosity (log⟨LLyα/[erg s−1]⟩ = 42.34) LAEs we calculated bhigh = 2.65−0.11+0.13 b high = 2. 65 − 0.11 + 0.13 $ b_\mathrm{{high}}=2.65^{+0.13}_{-0.11} $. Consequently, high-luminosity LAEs occupy dark matter halos (DMHs) with typical masses of log(Mh/[h−1 M⊙]) = 11.09−0.09+0.10 log (M h / [ h − 1 M ⊙ ]) = 11. 09 − 0.09 + 0.10 $ \log (M_{\mathrm{h}}/[h^{-1}M_\odot])=11.09^{+0.10}_{-0.09} $ , while low-luminosity LAEs reside in halos of log(Mh/[h−1 M⊙]) = 10.77−0.15+0.13 log (M h / [ h − 1 M ⊙ ]) = 10. 77 − 0.15 + 0.13 $ \log (M_{\mathrm{h}}/[h^{-1}M_\odot])=10.77^{+0.13}_{-0.15} $. The minimum masses to host one central LAE, Mmin, and (on average) one satellite LAE, M1, also vary with Lyα luminosity, growing from log(Mmin/[h−1M⊙]) = 10.3−0.3+0.2 log (M min / [ h − 1 M ⊙ ]) = 10. 3 − 0.3 + 0.2 $ \log (M_\mathrm{{min}}/[h^{-1}M_\odot])=10.3^{+0.2}_{-0.3} $ and log(M1/[h−1 M⊙]) = 11.7−0.2+0.3 log (M 1 / [ h − 1 M ⊙ ]) = 11. 7 − 0.2 + 0.3 $ \log (M_1/[h^{-1}M_\odot])=11.7^{+0.3}_{-0.2} $ to log(Mmin/[h−1 M⊙]) = 10.7−0.3+0.2 log (M min / [ h − 1 M ⊙ ]) = 10. 7 − 0.3 + 0.2 $ \log (M_\mathrm{{min}}/[h^{-1}M_\odot])=10.7^{+0.2}_{-0.3} $ and log(M1/[h−1 M⊙]) = 12.4−0.6+0.4 log (M 1 / [ h − 1 M ⊙ ]) = 12. 4 − 0.6 + 0.4 $ \log (M_1/[h^{-1}M_\odot])=12.4^{+0.4}_{-0.6} $ 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 LLyα. We report a strong (8σ) clustering dependence on Lyα luminosity, not accounting for cosmic variance effects, where the highest luminosity LAE subsample (log(LLyα/erg s−1) ≈ 42.53) clusters more strongly (bhighest = 3.13−0.15+0.08 b highest = 3. 13 − 0.15 + 0.08 $ b_\mathrm{{highest}}=3.13^{+0.08}_{-0.15} $) and resides in more massive DMHs (log(Mh/[h−1M⊙] )= 11.43−0.10+0.04 log (M h / [ h − 1 M ⊙ ]) = 11. 43 − 0.10 + 0.04 $ \log(M_\mathrm{{h}} / [h^{-1}{M}_{\odot}])=11.43^{+0.04}_{-0.10} $) than the lowest luminosity one (log(LLyα/erg s−1) ≈ 40.97), which presents a bias of blowest = 1.79−0.06+0.08 b lowest = 1. 79 − 0.06 + 0.08 $ b_\mathrm{{lowest}}=1.79^{+0.08}_{-0.06} $ and occupies log(Mh/[h−1M⊙]) = 10.00−0.09+0.12 log (M h / [ h − 1 M ⊙ ]) = 10. 00 − 0.09 + 0.12 $ \log(M_\mathrm{{h}} / [h^{-1}{M}_{\odot}])=10.00^{+0.12}_{-0.09} $ halos. We discuss the implications of these results for evolving Lyα luminosity functions, halo mass dependent Lyα escape fractions, and incomplete reionization signatures. [ABSTRACT FROM AUTHOR]