Neutrino mass, dark energy, and the linear growth factor
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT (United Kingdom)
- Institute of Theoretical Astrophysics, University of Oslo, Box 1029, 0315 Oslo (Norway)
We study the degeneracies between neutrino mass and dark energy as they manifest themselves in cosmological observations. In contradiction to a popular formula in the literature, the suppression of the matter power spectrum caused by massive neutrinos is not just a function of the ratio of neutrino to total mass densities f{sub {nu}}={omega}{sub {nu}}/{omega}{sub m}, but also each of the densities independently. We also present a fitting formula for the logarithmic growth factor of perturbations in a flat universe, f(z,k;f{sub {nu}},w,{omega}{sub DE}){approx_equal}[1-A(k){omega}{sub DE}f{sub {nu}}+B(k)f{sub {nu}}{sup 2}-C(k)f{sub {nu}}{sup 3}]{omega}{sub m}{sup {alpha}}(z), where {alpha} depends on the dark energy equation of state parameter w. We then discuss cosmological probes where the f factor directly appears: peculiar velocities, redshift distortion, and the integrated Sachs-Wolfe effect. We also modify the approximation of Eisenstein and Hu [Astrophys. J. 511, 5 (1999)] for the power spectrum of fluctuations in the presence of massive neutrinos and provide a revised code [http://www.star.ucl.ac.uk/{approx}lahav/nu{sub m}atter{sub p}ower.f].
- OSTI ID:
- 21249781
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 77, Issue 6; Other Information: DOI: 10.1103/PhysRevD.77.063005; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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