Population III X-ray Binaries and their Impact on the Early Universe

Understand

The first population of X-ray binaries (XRBs) is expected to affect the thermal and ionization states of the gas in the early Universe.

• Although these X-ray sources are predicted to have important implications for high-redshift observable signals, such as the hydrogen 21-cm signal from cosmic dawn and the cosmic X-ray background, their properties are poorly explored, leaving theoretical models largely uninformed.
• In this paper we model a population of X-ray binaries arising from zero metallicity stars.
• We explore how their properties depend on the adopted initial mass function (IMF) of primordial stars, finding a strong effect on their number and X-ray production efficiency.