%0 Generic %1 dijkstra2016lyalyc %A Dijkstra, Mark %A Gronke, Max %D 2016 %K connection lya lyc %T The LyA-LyC Connection: Evidence for an Enhanced Contribution of UV-faint Galaxies to Cosmic Reionization %U http://arxiv.org/abs/1604.08208 %X The escape of ionizing Lyman Continuum (LyC) photons requires the existence of low-N_HI sightlines, which also promote escape of Lyman-Alpha (Lya). We use a suite of 2500 Lya Monte-Carlo radiative transfer simulations through models of dusty, clumpy interstellar (`multiphase') media from Gronke & Dijkstra (2016), and compare the escape fractions of Lya f_esc(Lya) and LyC radiation f_esc(LyC). We find that f_esc(LyC) and f_esc(Lya) are correlated: galaxies with a low f_esc(Lya) consistently have a low f_esc(LyC), while galaxies with a high f_esc(Lya) exhibit a large dispersion in f_esc(LyC). We argue that there is increasing observational evidence that Lya escapes more easily from UV-faint galaxies. The correlation between f_esc(LyC) and f_esc(Lya) then implies that UV-faint galaxies contribute more to the ionizing background than implied by the faint-end slope of the UV-luminosity function. In multiphase gases, the ionizing escape fraction is most strongly affected by the cloud covering factor, f_cl, which implies that f_esc(LyC) is closely connected to the observed Lya spectral line shape. Specifically, LyC emitting galaxies typically having narrower, more symmetric line profiles. This prediction is qualitatively similar to that for `shell models'.

@misc{dijkstra2016lyalyc, abstract = {The escape of ionizing Lyman Continuum (LyC) photons requires the existence of low-N_HI sightlines, which also promote escape of Lyman-Alpha (Lya). We use a suite of 2500 Lya Monte-Carlo radiative transfer simulations through models of dusty, clumpy interstellar (`multiphase') media from Gronke & Dijkstra (2016), and compare the escape fractions of Lya [f_esc(Lya)] and LyC radiation [f_esc(LyC)]. We find that f_esc(LyC) and f_esc(Lya) are correlated: galaxies with a low f_esc(Lya) consistently have a low f_esc(LyC), while galaxies with a high f_esc(Lya) exhibit a large dispersion in f_esc(LyC). We argue that there is increasing observational evidence that Lya escapes more easily from UV-faint galaxies. The correlation between f_esc(LyC) and f_esc(Lya) then implies that UV-faint galaxies contribute more to the ionizing background than implied by the faint-end slope of the UV-luminosity function. In multiphase gases, the ionizing escape fraction is most strongly affected by the cloud covering factor, f_cl, which implies that f_esc(LyC) is closely connected to the observed Lya spectral line shape. Specifically, LyC emitting galaxies typically having narrower, more symmetric line profiles. This prediction is qualitatively similar to that for `shell models'.}, added-at = {2016-04-29T09:44:45.000+0200}, author = {Dijkstra, Mark and Gronke, Max}, biburl = {https://www.bibsonomy.org/bibtex/2a3f25e56e01ad04dbacb0f5c92ea1ec5/miki}, description = {[1604.08208] The LyA-LyC Connection: Evidence for an Enhanced Contribution of UV-faint Galaxies to Cosmic Reionization}, interhash = {4f93ca5e8e35d6faa88d3d7a64b85c54}, intrahash = {a3f25e56e01ad04dbacb0f5c92ea1ec5}, keywords = {connection lya lyc}, note = {cite arxiv:1604.08208Comment: 10 pages, 5 figures, submitted to ApJ}, timestamp = {2016-04-29T09:44:45.000+0200}, title = {The LyA-LyC Connection: Evidence for an Enhanced Contribution of UV-faint Galaxies to Cosmic Reionization}, url = {http://arxiv.org/abs/1604.08208}, year = 2016 }