Large scale structure from viscous dark matter

• Verfasst von: Blas, Diego [VerfasserIn]
• Verfasst von: Flörchinger, Stefan [VerfasserIn]
• Titel: Large scale structure from viscous dark matter
• Verf.angabe: Diego Blas, Stefan Floerchinger, Mathias Garny, Nikolaos Tetradis and Urs Achim Wiedemann
• E-Jahr: 2015
• Jahr: 30 November 2015
• Umfang: 30 S.
• Fussnoten: Gesehen am 24.11.2017
• Titel Quelle: Enthalten in: Journal of cosmology and astroparticle physics
• Ort Quelle: London : IOP, 2003
• Jahr Quelle: 2015
• Band/Heft Quelle: (2015), 11, Artikel-ID 049, Seite 1-30
• ISSN Quelle: 1475-7516
• DOI: doi:10.1088/1475-7516/2015/11/049
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1565711203

Abstract

Cosmological perturbations of sufficiently long wavelength admit a fluid dynamic description. We consider modes with wavevectors below a scale k m for which the dynamics is only mildly non-linear. The leading effect of modes above that scale can be accounted for by effective non-equilibrium viscosity and pressure terms. For mildly non-linear scales, these mainly arise from momentum transport within the ideal and cold but inhomogeneous fluid, while momentum transport due to more microscopic degrees of freedom is suppressed. As a consequence, concrete expressions with no free parameters, except the matching scale k m , can be derived from matching evolution equations to standard cosmological perturbation theory. Two-loop calculations of the matter power spectrum in the viscous theory lead to excellent agreement with N -body simulations up to scales k=0.2 h /Mpc. The convergence properties in the ultraviolet are better than for standard perturbation theory and the results are robust with respect to variations of the matching scale.