Linear cosmological structure limits on warm dark matter

Kevork Abazajian

Phys. Rev. D 73, 063513 – Published 17 March 2006

Abstract

I consider constraints from observations on a cutoff scale in clustering due to free streaming of the dark matter in a warm dark matter cosmological model with a cosmological constant. The limits are derived in the framework of a sterile neutrino warm dark matter universe, but can be applied to gravitinos and other models with small-scale suppression in the linear matter power spectrum. With freedom in all cosmological parameters including the free streaming scale of the sterile neutrino dark matter, limits are derived using observations of the fluctuations in the cosmic microwave background, the 3D clustering of galaxies and 1D clustering of gas in the Lyman-alpha ( $Ly α$ ) forest in the Sloan Digital Sky Survey (SDSS), as well as the $Ly α$ forest in high-resolution spectroscopic observations. In the most conservative case, using only the SDSS main-galaxy 3D power-spectrum shape, the limit is $m_{s} > 0.11 keV$ ; including the SDSS $Ly α$ forest, this limit improves to $m_{s} > 1.7 keV$ . More stringent constraints may be placed from the inferred matter power spectrum from high-resolution $Ly α$ forest observations, which has significant systematic uncertainties; in this case, the limit improves to $m_{s} > 3.0 keV$ (all at 95% CL).

Received 2 January 2006

DOI:https://doi.org/10.1103/PhysRevD.73.063513

Authors & Affiliations

Kevork Abazajian

Theoretical Division, MS B285, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA

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Vol. 73, Iss. 6 — 15 March 2006

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Images

Figure 1
Shown are the resulting linear matter power spectra $P (k)$ for a standard flat cosmological model $Ω_{DM} = 0.26$ , $σ_{8} = 0.9$ , $Ω_{b} = 0.04$ , and $h = 0.7$ at $z = 0$ , and with sterile neutrino warm to cold dark matter in the mass range $0.3 keV < m_{s} < 140 keV$ (gray/cyan). The corresponding CDM case is dashed (black). Small-scale clustering data used here are the SDSS 3D power-spectrum of galaxies (diamonds), the inferred slope and amplitude of the matter power spectrum from SDSS $Ly α$ forest observations (star point and slope between arrows), the inferred matter power spectrum from $Ly α$ forest observations from Croft et al. [32] (cross points) and the LUQAS (square points), as interpreted by VHS [33]. $Ly α$ forest measures are evolved to $z = 0$ by the appropriate growth function. The solid (blue) line at high- $k$ is $P (k)$ for upper limit $m_{s} = 8.2 keV$ from observations of Virgo [56], the solid (red) line at low- $k$ is that for the lower limit from the SDSS $Ly α$ forest in this work ( $m_{s} = 1.7 keV$ ), and the dotted line is that for the lower limit using high-resolution $Ly α$ forest data from this work ( $m_{s} = 3.0 keV$ ).Reuse & Permissions
Figure 2
Shown here are the 1D marginalized likelihoods on chosen base and derived cosmological parameters for the CMB plus SDSS 3D $P_{g} (k)$ in solid (blue), plus SDSS $Ly α$ forest in dashed (purple), plus the VHS high-resolution $Ly α$ forest in the dotted (red) line. The shaded (yellow) likelihoods are for the CMB plus SDSS 3D $P_{g} (k)$ plus SDSS $Ly α$ forest for the standard CDM case, which shows that parameters are generally not biased when including the presence of WDM.Reuse & Permissions
Figure 3
Shown here are the 1D marginalized likelihoods for the (inverse) mass of the sterile neutrino dark matter, $m_{s}$ and the scale of the primordial spectrum cutoff $α$ , from the CMB plus SDSS 3D $P_{g} (k)$ in the solid (blue) line, plus SDSS $Ly α$ forest in the dashed (purple) line, and plus the VHS high-resolution $Ly α$ forest in the dotted (red) line.Reuse & Permissions
Figure 4
The parameter space for sterile neutrino dark matter production and constraints. The red (dark gray) band is consistent with sterile neutrinos composing the dark matter consistent with $Ω_{DM} = 0.24 \pm 0.04$ [28]. Upper limits arise from radiative decay limits from XMM-Newton x-ray observations of the Virgo Cluster [56] and the diffuse x-ray background [58]. The lower limits of this work from the CMB plus SDSS 3D $P_{g} (k)$ plus SDSS $Ly α$ are in solid (yellow) at $m_{s} < 1.7 keV$ and all previous data plus VHS in dashed (yellow) at $m_{s} < 3.0 keV$ .Reuse & Permissions

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