The effect of ionizing background fluctuations on the spatial correlations of high redshift Ly$α$-emitting galaxies

Abstract

We investigate the possible influence of fluctuations in the metagalactic photoionizing ultra-violet background (UVBG) on the clustering of Lyα-emitting galaxies through the modulation of the ionization level of the gas surrounding the systems. At redshifts z > 5, even when assuming the reionization of the intergalactic medium has completed, the fluctuations are sufficiently large that they may non-negligibly enhance, and possibly even dominate, the angular correlation function on scales up to a few hundred arcsecs. Whilst a comparison with observations at z 5.7 is statistically consistent with no influence of UVBG fluctuations, allowing for the fluctuations opens up the range of acceptable models to include those with relatively low bias factors for the Lyα-emitting galaxies. In this case, the evolution in the bias factor of Lyα-emitters over the approximate redshift range 3 < z < 7 corresponds to a nearly constant halo mass for Lyα-emitting galaxies of ∼ 10 10.5 M .