Clustering of Ly-alpha emitters around luminous quasars at z = 2-3: an alternative probe of reionization on galaxy formation

TL;DR

This study uses the absence of Ly-alpha emitters around a luminous quasar at z=2.168 to infer that quasar radiation suppresses star formation in nearby galaxies, providing insights into galaxy formation during reionization.

Contribution

The paper introduces a semi-analytic model to quantify how luminous quasars influence the detectability of Ly-alpha emitters, linking quasar radiation to galaxy formation suppression.

Findings

Null detection implies host halo temperatures >3.4 million K

Corresponds to a virial mass of ~1.2 x 10^12 solar masses

Quasar UV emission likely suppresses nearby galaxy star formation

Abstract

Narrowband observations have detected no Ly-alpha emission within a 70 pMpc^3 volume centered on the z = 2.168 quasar PKS 0424-131. This is in contrast to surveys of Ly-alpha emitters in the field at similar redshifts and flux limits, which indicate that tens of sources should be visible within the same volume. The observed difference indicates that the quasar environment has a significant influence on the observed density of Ly-alpha emitters. To quantify this effect we have constructed a semi-analytic model to simulate the effect of a luminous quasar on nearby Ly-alpha emitters. We find the null detection around PKS 0424-131 implies that the minimum isothermal temperature of Ly-alpha emitter host halos is greater than 3.4 x 10^6 K (68% level), corresponding to a virial mass of ~1.2 x 10^12 M_solar. This indicates that the intense UV emission of the quasar may be suppressing the star formation in nearby galaxies. Our study illustrates that low redshift quasar environments may serve as a surrogate for studying the radiative suppression of galaxy formation during the epoch of reionization.