MUSEQuBES: the relation between Ly α emitters and C iv absorbers at z ≈ 3.3

Abstract

ABSTRACT We present a detailed study of the column density and covering fraction profiles of C iv absorption around 86 redshift z ≈ 3.3 Ly α emitters (LAEs) detected in eight Multi-Unit Spectroscopic Explorer (MUSE) fields of 1 arcmin × 1 arcmin centred on eight bright background quasars as part of the MUSE Quasar-field Blind Emitters Survey (MUSEQuBES). Using Voigt profile fitting of all the C iv absorbers detected along these eight sightlines, we generated a ‘blind’ absorber catalogue consisting of 489 C iv absorption components. We cross-matched this blind C iv catalogue with the MUSE-detected LAE catalogue and found a significant enhancement of C iv components within ≈±400 $\rm km\, s^{-1}$ of the systemic redshifts of the LAEs. Neither the C iv column density (N) nor the Doppler parameter (b) of individual C iv components shows any significant anticorrelation with impact parameter (ρ) of the LAEs in the 68 percentile range of 90 ≤ ρ ≤ 230 physical kpc (pkpc). We find a covering fraction of ≈60 per cent for a threshold $N(\rm{C{\small IV}})$ of 1012.5 cm−2, which is roughly twice as high as in random regions. The C iv covering fraction remains constant at $\approx\!{50}{{\ \rm per\, cent}}$ for impact parameters in the range of 150–250 pkpc (≈3–6R200). Using the covering fraction profile, we constrain the LAE–C iv absorber two-point correlation function, and obtain $r_0 = 3.4^{+1.1}_{-1.0}$ comoving Mpc and $\gamma = 1.2^{+0.2}_{-0.3}$ for a threshold $N(\rm{C{\small IV}})$ of 1013.0 cm−2. The C iv covering fraction is found to be enhanced for the LAEs that are part of a ‘pair/group’ compared to the isolated ones.