Ionizing photon production and escape fractions during cosmic reionization in the TNG50 simulation

Understand

In this work we investigate the dependence of the escape fraction of ionizing photons, $f_{\rm esc}$, on various galaxy and host halo properties during the epoch of reionization.

• We post-process the TNG50 magneto-hydrodynamical simulation from the IllustrisTNG project using the 3D multi-frequency radiative transfer code CRASH.
• Our work covers the stellar mass range $10^6 \lesssim M_\star/{\rm M_\odot} \lesssim 10^8$ at redshifts $6 < z < 10$.
• Adopting an unresolved, cloud-scale escape fraction parameter of unity, the halo escape fraction $f_{\rm esc}$ increases with mass from $\sim 0.3$ at $M_\star = 10^6$M$_\odot$ to $\sim 0.6$ at $M_\star = 10^{7.5}$M$_\odot$, after which we find hints of a turnover and decreasing escape fractions for even more massive galaxies.