Thermal constraints on the reionization of hydrogen by Population II stellar sources

Abstract

Measurements of the intergalactic medium (IGM) temperature provide a potentially powerful constraint on the reionization history due to the thermal imprint left by the photoionization of neutral hydrogen. However, until recently IGM temperature measurements were limited to redshifts 2 ≤z≤ 4.8, restricting the ability of these data to probe the reionization history at z > 6. In this work, we use recent measurements of the IGM temperature in the near-zones of seven quasars at z∼ 5.8-6.4, combined with a semi-numerical model for inhomogeneous reionization, to establish new constraints on the redshift at which hydrogen reionization completed. We calibrate the model to reproduce observational con..