Advances in Astronomy and Space Physics, Volume 4, Issue 1-2, PP. 9-14 (2014)
doi: 10.17721/2227-1481.4.9-14

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

D. A. Iakubovskyi

Bogolyubov Institute of Theoretical Physics, Metrologichna str. 14-b, 03680, Kyiv, Ukraine

Abstract
Recent works of Bulbul et al. (2014) and Boyarsky et al. (2014), claiming the detection of the extra emission line with energy ∼3.5 keV in X-ray spectra of certain clusters of galaxies and nearby Andromeda galaxy, have raised a 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 summarise 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.

Keywords:
X-rays: general, dark matter, line: identification