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

We investigate the possible influence of fluctuations in the metagalactic photoionizing ultra-violet background (UVBG) on the clustering of Ly$α$-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 $z \sim 5.7$ 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 Ly$α$-emitting galaxies. In this case, the evolution in the bias factor of Ly$α$-emitters over the approximate redshift range $3 < z < 7$ corresponds to a nearly constant halo mass for Ly$α$-emitting galaxies of $\sim 10^{10.5}\,M_\odot$.

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