Göttingen 2012 – wissenschaftliches Programm

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GR: Fachverband Gravitation und Relativitätstheorie

GR 3: Kosmologie II

GR 3.1: Vortrag

Montag, 27. Februar 2012, 16:40–17:00, ZHG 002

Bulk Viscous Universes — •Hermano Velten — Fakultät für Physik, Bielefeld Universität, Bielefeld, Germany

In this contribution we model Cold Dark Matter (CDM) as a non-ideal fluid. Ideal (or perfect) fluids are assumed to be dissipationless. On the other hand, real fluids display dissipative properties. In our model the CDM has an intrisic bulk viscous pressure given by Eckart’s formula p_v=−3H ξ, where 3H is the expansion scalar and ξ is the coefficient of bulk viscosity. We explore scenarios where i) the Universe is dominated by the viscous dark fluid (VDF) and ii) only the CDM component of the ΛCDM model behaves as a VDF. We constrain the background dynamics of these models using current astronomical data and we discuss the structure formation process in these scenarios (giving particular attention to the integrated Sachs-Wolfe effect).