Hitomi observations of Perseus with the Soft X-ray Spectrometer ( SXS ) provide a high-resolution look at the 3.5 keV feature reported by multiple groups in the Perseus cluster .
The Hitomi spectrum – which involves the sum of diffuse cluster emission and the point-like central Active Galactic Nucleus ( AGN ) – does not show any excess at E \sim 3.5 { keV } , giving an apparent inconsistency with previous observations of excess diffuse emission .
We point out that 2009 Chandra data reveals a strong dip in the AGN spectrum at E = ( 3.54 \pm 0.02 ) { keV } ( cluster frame ) – the identical energy to the diffuse excess observed by XMM-Newton .
Scaling this dip to the 2016 AGN luminosity and adding it to the diffuse XMM-Newton excess , this predicts an overall dip in the SXS field of view of ( -5.9 \pm 4.4 ) \times 10 ^ { -6 } { ph } { cm } ^ { -2 } { s } ^ { -1 } at E = 3.54 keV – a precise match to the Hitomi data when broadened by the dark matter virial velocity .
We describe models of Fluorescent Dark Matter that can reproduce this physics , in which dark matter absorbs and then re-emits 3.5 keV photons emitted from the central AGN .