SIMBAD references

We present rest-frame Lyα equivalent widths (EW₀) of 417 Lyα emitters (LAEs) detected with Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope (VLT) at 2.9<z<6.6 in the Hubble Ultra Deep Field. Based on the deep MUSE spectroscopy and ancillary Hubble Space Telescope (HST) photometry data, we carefully measured EW₀ values taking into account extended Lyα emission and UV continuum slopes (β). Our LAEs reach unprecedented depths, both in Lyα luminosities and UV absolute magnitudes, from log(L_Lyα/erg/s)∼41.0 to 43.0 and from M_UV~-16 to -21 (0.01-1.0L*_z=3). The EW₀ values span the range of ∼5 to 240Å or larger, and their distribution can be well fitted by an exponential law N=N₀exp(-EW₀/w₀). Owing to the high dynamic range in M_UV, we find that the scale factor, w₀, depends on M_UV in the sense that including fainter M_UV objects increases w₀, i.e., the Ando effect. The results indicate that selection functions affect the EW₀ scale factor. Taking these effects into account, we find that our w₀ values are consistent with those in the literature within 1σ uncertainties at 2.9<z<6.6 at a given threshold of M_UV and L_Lyα. Interestingly, we find 12 objects with EW₀>200Å above 1σ uncertainties. Two of these 12 LAEs show signatures of merger or AGN activity: the weak CIVλ1549 emission line. For the remaining 10 very large EW₀ LAEs, we find that the EW₀ values can be reproduced by young stellar ages (<100Myr) and low metallicities (≤0.02Z_☉). Otherwise, at least part of the Lyα emission in these LAEs needs to arise from anisotropic radiative transfer effects, fluorescence by hidden AGN or quasi-stellar object activity, or gravitational cooling.