SUSY in the sky or a keV signature of sub-GeV gravitino dark matter

We point out that recently discovered 3.5 keV line in X-ray spectra from various galaxy clusters and the Andromeda galaxy can be naturally explained by physics of a sector responsible for spontaneous supersymmetry breaking in models with R-parity. In this scenario the source of this line could be decay of sgoldstino - scalar superpartner of massive gravitino. At the same time the dominant dark matter component is stable gravitino whose mass is predicted to be about 0.25 GeV.
Comment: 8 pages, published version