The Lyman-alpha forest as a diagnostic of the nature of the dark matter

TY - JOUR

T1 - The Lyman-alpha forest as a diagnostic of the nature of the dark matter

AU - Garzilli, Antonella

AU - Magalich, Andrii

AU - Theuns, Tom

AU - Frenk, Carlos S.

AU - Weniger, Christoph

AU - Ruchayskiy, Oleg

AU - Boyarsky, Alexey

PY - 2019/11/1

Y1 - 2019/11/1

N2 - The observed Lyman-α flux power spectrum (FPS) is suppressed on scales below∼30 km s-1. This cut-off could be due to the high temperature, T0, and pressure, p0, 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 T0, p0, 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.

AB - The observed Lyman-α flux power spectrum (FPS) is suppressed on scales below∼30 km s-1. This cut-off could be due to the high temperature, T0, and pressure, p0, 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 T0, p0, 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.

KW - methods: data analysis

KW - intergalactic medium

KW - quasars: absorption lines

KW - dark matter

KW - large-scale structure of Universe

U2 - 10.1093/mnras/stz2188

DO - 10.1093/mnras/stz2188

M3 - Journal article

SN - 0035-8711

VL - 489

SP - 3456

EP - 3471

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 3

ER -