Swift observation of Segue 1: constraints on sterile neutrino parameters in the darkest galaxy

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Author/Creator ORCID

Date

2010-11-01

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Citation of Original Publication

N. Mirabal, Swift observation of Segue 1: constraints on sterile neutrino parameters in the darkest galaxy, Monthly Notices of the Royal Astronomical Society: Letters, Volume 409, Issue 1, November 2010, Pages L128–L131, https://doi.org/10.1111/j.1745-3933.2010.00963.x

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This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society: Letters Published by Oxford University Press on behalf of the Royal Astronomical Society.

Subjects

Abstract

Some extensions of standard particle physics postulate that dark matter may be partially composed of weakly interacting sterile neutrino particles that have so far eluded detection. We use a short (∼5 ks) archival X-ray observation of Segue 1 obtained with the X-ray Telescope (XRT) onboard the Swift satellite to exclude the presence of sterile neutrinos in the 1.6–14 keV mass range down to a flux limit of 6 × 10⁻¹² erg cm⁻² s⁻¹ within 67 pc of its centre. With an estimated mass-to-light ratio of ∼3400 M⊙/L⊙, Segue 1 is the darkest ultrafaint dwarf galaxy currently measured. Spectral analysis of the Swift XRT data fails to find any non-instrumental spectral feature possibly connected with the radiative decay of a dark matter particle. Accordingly, we establish upper bounds on the sterile neutrino parameter space based on the non-detection of emission lines in the spectrum. The present work provides the most sensitive X-ray search for sterile neutrinos in a region with the highest dark matter density yet measured.