Constraints on X-ray Emissions from the Reionization Era

Understand

We examine the constraints on soft X-ray emissions from the reionization era.

• It has generally been assumed that the Universe was reionized by ultraviolet photons from massive stars.
• However, it has been argued that X-ray photons associated with the death of these stars would have contributed ~10% to the total ionizations via several channels.
• The parameter space for a significant component of cosmological reionization to be sourced by X-rays is limited by a few observations.