Ponente
Descripción
The 3.5 keV line is a purported emission line observed in galaxies, galaxy clusters, and the Milky Way whose origin is inconsistent with known atomic transitions and has previously been suggested to arise from dark matter (DM) decay. I show why the line cannot arise from DM decay, and then describe work in which collaborators and I reanalyzed the datasets providing the bulk of the evidence for the 3.5 keV line. Surprisingly, we found a line in only one of those datasets; in the rest we found no evidence for a line, possibly due to the use of local optimization in earlier works. In the remaining dataset we present evidence for mismodeling that suggests the line is spurious. We conclude that there is no robust evidence for the existence of the 3.5 keV line. I finally discuss prospects for detecting X-ray lines with XRISM, a recently-launched telescope with 20 times better energy resolution than that of previous telescopes.
