Cluster X-ray line at $3.5\mathrm{keV}$ from axion-like dark matter

Hyun Min Lee, Seong Chan Park, Wan-Il Park

The recently reported X-ray line signal at $E_{\gamma }\simeq 3.5\mathrm{keV}$ from a stacked spectrum of various galaxy clusters and the Andromeda galaxy may be originating from a decayin…