SCORCH. II. Radiation-Hydrodynamic simulations of reionization with varying radiation escape fractions

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In the Simulations and Constructions of the Reionization of Cosmic Hydrogen (SCORCH) project, we present new radiation-hydrodynamic simulations with updated high-redshift galaxy populations and varying radiation escape fractions.

• The simulations are designed to have fixed Thomson optical depth $\tau \approx 0.06$, consistent with recent Planck observations, and similar midpoints of reionization $7.5 \lesssim z \lesssim 8.0$, but with different ionization histories.
• The galaxy luminosity functions and ionizing photon production rates in our model are in good agreement with recent HST observations.
• Adopting a power-law form for the radiation escape fraction $f_{\text{esc}}(z) = f_8[(1+z)/9]^{a_{8}}$, we simulate the cases for $a_8 = 0$, 1, and 2 and find $a_8 \lesssim 2$ in order to end reionization in the range $5.5 \lesssim z \lesssim 6.5$ to be consistent with Lyman alpha forest observations.