Speaker
Description
The Sunburst Arc (z~2.37) is a confirmed Lyman continuum leaker galaxy and has been uniquely lensed where its single leaking region is imaged 12 times over four separate arcs. Using HST/WFC3 UVIS G280 grism observations, we extracted the spectra of the leaking region to determine the shape of the stellar continuum from 600-900Å (produced by young, massive O and B stars) for the first time. The intrinsic Lyman continuum escape fraction is >70% leaving the interstellar medium, but foreground intergalactic medium (IGM) absorption lowers this estimate to ~30%. The same foreground IGM absorbers at z~2 are seen in multiple images, allowing us to constrain their physical size in 2D and estimate their HI mass. This rare sightline gives insight into the conditions necessary for the propagation of ionizing photons and can help interpret results from reionization.
