The Lyman-α forest as a diagnostic of the nature of the dark matter. Issue 3 (8th August 2019)

• Record Type: Journal Article
• Authors: Garzilli, Antonella; Magalich, Andrii; Theuns, Tom; Frenk, Carlos S; Weniger, Christoph; Ruchayskiy, Oleg; Boyarsky, Alexey
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 489:Issue 3(2019)
• Page Start: 3456
• Page End: 3471
• Publication Date: 2019-08-08
• Subjects: methods: data analysis -- intergalactic medium -- quasars: absorption lines -- dark matter -- large-scale structure of Universe; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stz2188
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: The observed Lyman-α flux power spectrum (FPS) is suppressed on scales below ${\sim} ~ 30\, {\rm km\, s}^{-1}$ . This cut-off could be due to the high temperature, T 0, and pressure, p 0, of the absorbing gas or, alternatively, it could reflect the free streaming of dark matter particles in the early universe. We perform a set of very high resolution cosmological hydrodynamic simulations in which we vary T 0, p 0, and the amplitude of the dark matter free streaming, and compare the FPS of mock spectra to the data. We show that the location of the dark matter free-streaming cut-off scales differently with redshift than the cut-off produced by thermal effects and is more pronounced at higher redshift. We, therefore, focus on a comparison to the observed FPS at z > 5. We demonstrate that the FPS cut-off can be fit assuming cold dark matter, but it can be equally well fit assuming that the dark matter consists of ∼7 keV sterile neutrinos in which case the cut-off is due primarily to the dark matter free streaming.