The Evolution of the Lyman-alpha Luminosity Function during Reionization

The time frame in which hydrogen reionization occurred is highly uncertain, but can be constrained by observations of Lyman-alpha (Ly$\alpha$) emission from distant sources. Neutral the intergalactic medium (IGM) attenuates Ly$\alpha$~photons emitted galaxies. As progressed IGM opacity decreased, increasing Ly$\alpha$~visibility. galaxy Ly$\alpha$~luminosity function (LF) thus a useful tool to constrain timeline reionization. In this work, we model Ly$\alpha$~LF as redshift, $z=5-10$, and average neutral fraction, $\overline{x}_\textsc{hi}$. We combine probability distribution obtained inhomogeneous simulations with for UV LF Ly$\alpha$~LF. fraction increases, number density Ly$\alpha$~emitting galaxies decreases, are less luminous, though $\overline{x}_\textsc{hi} \lesssim 0.4$ there only small decrease use our infer at $z=6.6, 7.0, 7.3$ observed Ly$\alpha$~LFs. conclude that significant increase redshift: $\overline{x}_\textsc{hi}(z=6.6)=0.08^{+ 0.08}_{- 0.05}, \, \overline{x}_\textsc{hi}(z=7.0)=0.28 \pm 0.05$ $\overline{x}_\textsc{hi}(z=7.3)=0.83^{+ 0.06}_{- 0.07}$. predict trends Schechter parameters redshift fraction. find decreases universe becomes more neutral. Furthermore, faint-end slope steepens, characteristic shifts lower values, concluding evolving shape -- not just its integral an important study