Speaker
Description
The reionisation of the IGM was driven by the first galaxies. However, the nature of these galaxies remains uncertain. This includes how many stars form in a galaxy, what types of stars form and what fraction of the ionising photons produced in the galaxy escape into the IGM. In particular, the ionising photon escape fraction is poorly constrained observationally and we lack a clear picture of which physical processes determine how ionising photons escape.
The distribution of escape fractions in galaxy samples can constrain which leakage mechanisms dominate. However, until now we only have average escape fraction estimates from galaxy samples or direct measurements of the escape fraction from individual galaxies. For 4 physically motivated models of the escape fraction distribution, we have used hierarchical Bayesian inference to constrain the escape fraction distribution from a sample of reionisation-era analogue ($3<z<4$) galaxies.
In this talk, I will present the inferred escape fraction distributions, discuss which of our models best describes the observed data and compare the best-fitting model to simulations. I will discuss what drives ionising photon escape and the implications on our understanding of reionisation.