ASTRAEUS - VIII. A new framework for Lyman-alpha emitters applied to different reionization scenarios

We use the ASTRAEUS framework to investigate how the visibility and spatial distribution of Lyman-alpha(Ly alpha) emitters (LAEs) during reionization is sensitive to a halo mass-dependent fraction of ionizing radiation escaping from the galactic environment (f(esc)) and the ionization topology. To this end, we consider the two physically plausible bracketing scenarios of f(esc) increasing and decreasing with rising halo mass. We derive the corresponding observed Lyaluminosities of galaxies for three different analytic Ly alpha line profiles and associated Ly alpha escape fraction (f(esc)(Lya)) models: importantly, we introduce two novel analytic Ly alpha line profile models that describe the surrounding interstellar medium (ISM) as dusty gas clumps. They are based on parameterizing results from radiative transfer simulations, with one of them relating f(esc)(Lya) to f(esc) by assuming the ISM of being interspersed with low-density tunnels. Our key findings are: (i) for dusty gas clumps, the Ly alpha line profile develops from a central to double peak dominated profile as a galaxy's halo mass increases; (ii) LAEs are galaxies with M-h greater than or similar to 10(10) M-circle dot located in overdense and highly ionized regions; (iii) for this reason, the spatial distribution of LAEs is primarily sensitive to the global ionization fraction and only weakly in second-order to the ionization topology or a halo mass-dependent f(esc); (iv) furthermore, as the observed Ly alpha luminosity functions reflect the Ly alpha emission from more massive galaxies, there is a degeneracy between the f(esc)-dependent intrinsic Ly alpha luminosity and the Ly alpha attenuation by dust in the ISM if f(esc) does not exceed similar to 50 per cent