Evidence of increased UV Fe ii emission in quasars in candidate overdense regions

We present evidence for a skewed distribution of UV Fe ii emission in quasars within candidate overdense regions spanning spatial scales of ∼50 Mpc at 1.11 < z < 1.67, compared to quasars in field environments at comparable redshifts. The overdense regions have an excess of high-equivalent-width sources (W2400 > 42 Å) and a dearth of low-equivalent-width sources. There are various possible explanations for this effect, including dust, Lyα fluorescence, microturbulence and iron abundance. We find that the most plausible of these is enhanced iron abundance in the overdense regions, consistent with an enhanced star formation rate in the overdense regions compared to the field.