New emission line at ~3.5 keV - observational status, connection with radiatively decaying dark matter and directions for future studies

Abstract

Recent works of [1402.2301,1402.4119], claiming the detection of extra emission line with energy ~3.5 keV in X-ray spectra of certain clusters of galaxies and nearby Andromeda galaxy, have raised considerable interest in astrophysics and particle physics communities. A number of new observational studies claim detection or non-detection of the extra line in X-ray spectra of various cosmic objects. In this review I summarize existing results of these studies, overview possible interpretations of the extra line, including intriguing connection with radiatively decaying dark matter, and show future directions achievable with existing and planned X-ray cosmic missions.

8 pages, invited review for Advances in Astronomy and Space Physics. Comments are welcome

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Cited by in corpus (2)

• A 3.55 keV line from $\text{DM}\to a\to \gamma$: predictions for cool-core and non-cool-core clusters
• A Couplet from Flavored Dark Matter