Direct X-ray Constraints on Sterile Neutrino Warm Dark Matter
Abstract
Warm dark matter (WDM) might more easily account for small scale clustering measurements than the heavier particles typically invoked in Lambda cold dark matter (LCDM) cosmologies. In this paper, we consider a Lambda WDM cosmology in which sterile neutrinos nu_s, with a mass m_s of roughly 1-100 keV, are the dark matter. We use the diffuse X-ray spectrum (total minus resolved point source emission) of the Andromeda galaxy to constrain the rate of sterile neutrino radiative decay: nu_s -> nu_{e,mu,tau} + gamma. Our findings demand that m_s < 3.5 keV (95% C.L.) which is a significant improvement over the previous (95% C.L.) limits inferred from the X-ray emission of nearby clusters, m_s < 8.2 keV (Virgo A) and m_s < 6.3 keV (Virgo A + Coma).
Cite
@article{arxiv.astro-ph/0605424,
title = {Direct X-ray Constraints on Sterile Neutrino Warm Dark Matter},
author = {Casey R. Watson and John F. Beacom and Hasan Yuksel and Terry P. Walker},
journal= {arXiv preprint arXiv:astro-ph/0605424},
year = {2009}
}
Comments
8 pages, 2 figures, minor revisions, accepted for publication in Physical Review D