Charge exchange in galaxy clusters

Understand

Though theoretically expected, the charge exchange emission from galaxy clusters has not yet been confidently detected.

• Accumulating hints were reported recently, including a rather marginal detection with the Hitomi data of the Perseus cluster.
• As suggested in Gu et al.
• (2015), a detection of charge exchange line emission from galaxy clusters would not only impact the interpretation of the newly-discovered 3.5 keV line, but also open up a new research topic on the interaction between hot and cold matter in clusters.