The Difficulty of Getting High Escape Fractions of Ionizing Photons from High-redshift Galaxies: a View from the FIRE Cosmological Simulations

Understand

We present a series of high-resolution (20-2000 Msun, 0.1-4 pc) cosmological zoom-in simulations at z~6 from the Feedback In Realistic Environment (FIRE) project.

• These simulations cover halo masses 10^9-10^11 Msun and rest-frame ultraviolet magnitude Muv = -9 to -19.
• These simulations include explicit models of the multi-phase ISM, star formation, and stellar feedback, which produce reasonable galaxy properties at z = 0-6.
• We post-process the snapshots with a radiative transfer code to evaluate the escape fraction (fesc) of hydrogen ionizing photons.