Wednesday, December 21, 2011

1112.4837 (Guillermo Ballesteros et al.)

Nonlinear cosmological consistency relations and effective matter stresses    [PDF]

Guillermo Ballesteros, Lukas Hollenstein, Rajeev Kumar Jain, Martin Kunz
We propose a completely nonlinear framework to construct consistency relations for testing generic cosmological scenarios using the evolution of large scale structure. It is based on the covariant approach in combination with a frame that is purely given by the metric, the normal frame. As an example, we apply this framework to the LCDM model, extending the usual first order conditions on the metric potentials to second order. We argue that working in the normal frame is not only a practical choice but one that closely resembles our actual situation as observers. In this frame, effective pressures and anisotropic stresses appear at second order in perturbation theory, even for dust. We quantify this effect and compare it, for illustration, with the pressure of a generic clustering dark energy fluid and the anisotropic stress in the DGP model. Besides, we also discuss the effect of a mismatch of the potentials on the determination of galaxy bias.
View original: http://arxiv.org/abs/1112.4837

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