The XMM Cluster Survey: new evidence for the 3.5 keV feature in clusters is inconsistent with a dark matter origin

Understand

There have been several reports of a detection of an unexplained excess of X-ray emission at $\simeq$ 3.5 keV in astrophysical systems.

• One interpretation of this excess is the decay of sterile neutrino dark matter.
• The most influential study to date analysed 73 clusters observed by the XMM-Newton satellite.
• We explore evidence for a $\simeq$ 3.5 keV excess in the XMM-PN spectra of 117 redMaPPer galaxy clusters ($0.1 < z < 0.6$).