A determination of the Lyman Alpha emitter luminosity function at z=3-6

New paper by E.C. Herenz et al.
We derive the Lyman Alpha Emitter (LAE) Luminosity Function using the first 24 fields in MUSE-Wide. We use a variety of non-parametric estimators, including the classical 1/Vmax method. When taking into account the extended shape of LAEs into the completeness function, we find steeper slopes in the Luminosity Function than other studies that assume LAEs are point sources.
Available here:
https://arxiv.org/abs/1810.05037

(Abridged) We investigate the Lyman

α emitter luminosity function (LAE LF) within the redshift range

2.9≤z≤6 from the first instalment of the blind integral field spectroscopic survey MUSE-Wide. This initial part of the survey probes a region of 22.2 arcmin

2 in the CANDELS/GOODS-S field. The dataset provided us with 237 LAEs from which we construct the LAE LF in the luminosity range

42.2≤logLLyα[ergs−1]≤43.5 within a volume of

2.3×105 Mpc

3. For the LF construction we utilise three different non-parametric estimators: The classical

1/Vmax method, the

C− method, and an improved binned estimator for the differential LF. All three methods deliver consistent results, with the cumulative LAE LF being

Φ(logLLyα[ergs−1]=43.5) ≃ 3×10−6 Mpc

−3 and

Φ(logLLyα[ergs−1]=42.2) ≃ 2×10−3 Mpc

−3 towards the bright- and faint-end of our survey, respectively. By employing a non-parametric statistical test, as well as by comparing the full sample to sub-samples in redshift bins, we find no supporting evidence for an evolving LAE LF over the probed redshift and luminosity range. We determine the best-fitting Schechter function parameters

α=−1.84+0.42−0.41 and

logL∗[ergs−1] = 42.2+0.22−0.16 with the corresponding normalisation

logϕ∗[Mpc−3]=−2.71. When correcting for completeness in the LAE LF determinations, we take into account that LAEs exhibit diffuse extended low surface-brightness haloes. We compare the resulting LF to one obtained where we apply a correction assuming compact point-like emission. We find that the standard correction underestimates the LAE LF at the faint end of our survey by a factor of 2.5.