X-Rays from e ^± Pair Halos

Abstract

It was previously suggested that e ^± pair halos could be observed in γ-rays. Searching for pair halos is a challenging topic in γ-ray astronomy that has not yet yielded a convincing detection for an individual object. Here we propose that X-ray observations could reveal the existence of e ^± pair halos. To support our suggestion, we computed the observed energy and spatial distribution of X-ray photons from the pair halos and check the feasibility of pair halo detection by current and future X-ray observatories. The results show that current X-ray missions could register a positive signal for the pair halos created under some conditions. For a magnetic field (B) of ∼1 μG, the X-ray could be observable for a seed gamma-ray energy of {E}_{{γ 0}}≳ 50 TeV. If {E}_{{γ 0}}∼ 100 TeV, the observable range of B would be B ≳ 300 nG.