Structure formation with causal bulk viscosity

Giovanni Acquaviva; Anslyn John; Aurélie Pénin

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arXiv · 1805.06363

Structure formation with causal bulk viscosity

Giovanni Acquaviva·Anslyn John·Aurélie Pénin

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Abstract

Dissipative features of dark matter affect its clustering properties and could lead to observable consequences for the evolution of large--scale structure. We analyse the evolution of cold dark matter density perturbations allowing for the possibility of bulk viscous pressure in a causal dissipative theory. Our analysis employs a Newtonian approximation for cosmological dynamics and the transport properties of bulk viscosity are described by the Israel--Stewart theory. We obtain a third order evolution equation for density perturbations. For some parameter values the density contrast can be suppressed compared to results obtained in the $\Lambda$CDM scenario. For other values causal bulk viscous dark matter can exhibit an enhancement of clustering.

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Giovanni Acquaviva, Anslyn John, Aurélie Pénin. 2018-05-16. Structure formation with causal bulk viscosity. https://arxiv.org/abs/1805.06363

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