Lyman-alpha constraints on warm and on warm-plus-cold dark matter models

2008/12/31 by Alexey Boyarsky, Julien Lesgourgues, Oleg Ruchayskiy +1 · 2 citations
Physics and Astronomy · #astro-ph #hep-ph

paper · pdf · doi:10.1088/1475-7516/2009/05/012

published as JCAP 05 (2009) 012 · 55 pages, 14 figures. References added, discussion of the data analysis expanded. Final version to appear in JCAP

arxiv created 2009/05/20 · arxiv updated 2015/05/12

Abstract

We revisit Lyman-alpha bounds on the dark matter mass in Lambda Warm Dark Matter (Lambda-WDM) models, and derive new bounds in the case of mixed Cold plus Warm models (Lambda-CWDM), using a set up which is a good approximation for several theoretically well-motivated dark matter models. We combine WMAP5 results with two different Lyman-alpha data sets, including observations from the Sloan Digital Sky Survey. We pay a special attention to systematics, test various possible sources of error, and compare the results of different statistical approaches. Expressed in terms of the mass of a non-resonantly produced sterile neutrino, our bounds read m_NRP > 8 keV (frequentist 99.7% confidence limit) or m_NRP > 12.1 keV (Bayesian 95% credible interval) in the pure Lambda-WDM limit. For the mixed model, we obtain limits on the mass as a function of the warm dark matter fraction F_WDM. Within the mass range studied here (5 keV < m_NRP < infinity), we find that any mass value is allowed when F_WDM < 0.6 (frequentist 99.7% confidence limit); similarly, the Bayesian joint probability on (F_WDM, 1/m_NRP) allows any value of the mass at the 95% confidence level, provided that F_WDM < 0.35.

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