Journal Article

Constraints on decaying dark matter from <i>XMM–Newton</i> observations of M31

Alexey Boyarsky, Dmytro Iakubovskyi, Oleg Ruchayskiy and Vladimir Savchenko

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 387, issue 4, pages 1361-1373
Published in print July 2008 | ISSN: 0035-8711
Published online July 2008 | e-ISSN: 1365-2966 | DOI:
Constraints on decaying dark matter from XMM–Newton observations of M31

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We derive constraints on the parameters of the radiatively decaying dark matter (DM) particle, using the XMM–Newton EPIC spectra of the Andromeda galaxy (M31). Using the observations of the outer (5–13 arcmin) parts of M31, we improve the existing constraints. For the case of sterile neutrino DM, combining our constraints with the latest computation of abundances of sterile neutrinos in the Dodelson–Widrow (DW) scenario, we obtain the lower mass limit ms < 4 keV, which is stronger than the previous one ms < 6 keV, obtained recently by Asaka, Laine & Shaposhnikov. Comparing this limit with the most recent results on Lyman α forest analysis of Viel et al. (ms > 5.6 keV), we argue that the scenario in which all the DM is produced via the DW mechanism is ruled out. We discuss, however, other production mechanisms and note that the sterile neutrino remains a viable candidate for DM, either warm or cold.

Keywords: methods: data analysis; galaxies: individual: Andromeda galaxy; dark matter; X-rays: individual: Andromeda galaxy

Journal Article.  9505 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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