Escape fraction of ionizing photons during reionization: effects due to supernova feedback and runaway OB stars

Understand

The fraction of hydrogen ionizing photons escaping from galaxies into the intergalactic medium is a critical ingredient in the theory of reionization.

• We use two zoomed-in, high-resolution (4 pc), cosmological radiation hydrodynamic simulations with adaptive mesh refinement to investigate the impact of two physical mechanisms (supernova feedback and runaway OB stars) on the escape fraction (f_esc) at the epoch of reionization (z>7).
• We implement a new, physically motivated supernova feedback model that can approximate the Sedov solutions at all (from the free expansion to snowplow) stages.
• We find that there is a significant time delay of about ten million years between the peak of star formation and that of escape fraction, due to the time required for the build-up and subsequent destruction of the star-forming cloud by supernova feedback.