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Reionisation in sterile neutrino cosmologies

Bose, S.; Frenk, C.S.; Hou, J.; Lacey, C.G.; Lovell, M.R.

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S. Bose

J. Hou

M.R. Lovell


We investigate the process of reionisation in a model in which the dark matter is a warm elementary particle such as a sterile neutrino. We focus on models that are consistent with the dark matter decay interpretation of the recently detected line at 3.5 keV in the X-ray spectra of galaxies and clusters. In warm dark matter models the primordial spectrum of density perturbations has a cut-off on the scale of dwarf galaxies. Structure formation therefore begins later than in the standard cold dark matter (CDM) model and very few objects form below the cut-off mass scale. To calculate the number of ionising photons, we use the Durham semi-analytic model of galaxy formation, GALFORM. We find that even the most extreme 7 keV sterile neutrino we consider is able to reionise the Universe early enough to be compatible with the bounds on the epoch of reionisation from Planck. This, perhaps surprising, result arises from the rapid build-up of high redshift galaxies in the sterile neutrino models which is also reflected in a faster evolution of their far-UV luminosity function between 10 > z > 7 than in CDM. The dominant sources of ionising photons are systematically more massive in the sterile neutrino models than in CDM. As a consistency check on the models, we calculate the present-day luminosity function of satellites of Milky Way-like galaxies. When the satellites recently discovered in the DES survey are taken into account, strong constraints are placed on viable sterile neutrino models.


Bose, S., Frenk, C., Hou, J., Lacey, C., & Lovell, M. (2016). Reionisation in sterile neutrino cosmologies. Monthly Notices of the Royal Astronomical Society, 463(4), 3848-3859.

Journal Article Type Article
Acceptance Date Sep 8, 2016
Online Publication Date Sep 12, 2016
Publication Date Dec 21, 2016
Deposit Date Sep 28, 2016
Publicly Available Date Oct 6, 2016
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 463
Issue 4
Pages 3848-3859


Published Journal Article (Final published version) (1.2 Mb)

Copyright Statement
Final published version

Published Journal Article (Advance online version) (803 Kb)

Copyright Statement
Advance online version This article has been published in Monthly Notices of the Royal Astronomical Society ©: 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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