Le 22 décembre 2017
De 10h30 à 12h00
Max Gronke
UC Santa Barbara
The Lyman-alpha (Lya) of neutral hydrogen is the most prominent emission line in the Universe, and since its it provides a unique window into the high redshift Universe. I will discuss some examples of how Lya observables can be used to study, for instance, the Epoch of Reionization, and the composition of the interstellar and circumgalactic medium. To do this I will present some efforts on the modelling of the Lya luminosity function, and what we might learn from this regarding the escape of ionizing photons. Furthermore, I will give a brief introduction to Lya radiative transfer. This will include some more recent results which suggest that small-scale structure is critical in influencing resonant line radiative transfer, and that the Lya spectrum is in fact sensitive to features on far smaller scales than other observational techniques. These results might explain a number of puzzling observations, including evidence for tiny-scale structure in the gas and the fact that the spectra are best fit by homogeneous models, despite our knowledge that the ISM and CGM are multiphase.