Characterizing Strongly-Lensed Lyman-Alpha Galaxies at z > 4

Lyman-alpha is one of the most important tools for studying star-forming regions in young galaxies. As Hydrogen's brightest recombination line, it is an excellent tracer for star formation during the Epoch of Reionization. However, through complex radiative transfer, Lyman-alpha is highly sensitive to non- isotropic distributions of neutral hydrogen. Previous studies of high-redshift Lyman-alpha Emitters (LAEs) have been limited in spatial resolution, barely able to resolve sub-galactic scales, especially in smaller high-redshift galaxies. Strong gravitational lensing studies of Lyman-alpha in the high redshift universe give us an opportunity to probe spatial scales that are otherwise inaccessible. We present six strongly gravitationally lensed LAEs at 4.1 < z < 5.2 with high signal-to-noise HST narrowband imaging isolating Lyman-alpha. Broadband imaging from \HST (rest-frame UV) and Spitzer (rest-frame optical) is used in SED fitting, providing physical context to the LAEs. Lens models are used to determine the intrinsic, source-plane properties of the LAEs, such as mass, brightness, and physical scale. We examine the LAE morphologies in Lyman-alpha and the stellar continuum, finding that they fall into two broad categories: extended galaxy-scale halos and clumpy emission dispersed among the UV continuum. The range of Lyman-alpha extent in this sample suggests that LAEs in the distant universe are not a homogeneous class of objects.