The long-lasting effect of X-ray preheating in the post-reionization intergalactic medium

Understand

X-ray photons can penetrate deep into the intergalactic medium (IGM), leading to preheating of the IGM prior to cosmic reionization.

• X-ray preheating wipes out some of the small-scale structures that would otherwise be present prior to the passage of an ionization front.
• Accurate modeling of the small-scale structure is vital to the post-reionization IGM since the small-scale structure is ultimately the dominant source of long-lasting relics from hydrogen reionization.
• However, the precise impact of X-ray preheating in the fossils from hydrogen reionization is highly uncertain.