Spherical collapse for unified dark matter models

Abstract

We study the non-linear spherical "top hat" collapse for Chaplygin and viscous unified cosmologies. The term unified refers to models where dark energy and dark matter are replaced by one single component. For the generalized Chaplygin gas (GCG) we extend previous results of [R. A. A. Fernandes {\it et al}. Physical Review D 85, 083501 (2012)]. We discuss the differences at non-linear level between the GCG with $\alpha =0$ and the $\Lambda$CDM model. We show that both are indeed different. The bulk viscous model which differs from the GCG due to the existence of non-adiabatic perturbations is also studied. In this case, the clustering process is in general suppressed and the viable parameter space of the viscous model that accelerates the background expansion does not lead to collapsed structures. This result challenges the viability of unified viscous models.

7 pages, 12 figures

References in corpus (6)

• Does Bulk Viscosity Create a Viable Unified Dark Matter Model?
• Dissipation of dark matter
• Non-adiabatic dark fluid cosmology
• Shear and rotation in Chaplygin cosmology
• Dynamical Mutation of Dark Energy
• Linear and non-Linear Instabilities in Unified Dark Energy Models

Cited by in corpus (9)

• Structure formation in a $\Lambda$ $viscous$ CDM universe
• Assessing the impact of bulk and shear viscosities on large scale structure formation
• Dark sector impact on gravitational collapse of an electrically charged scalar field
• Non-linear clustering during the BEC dark matter phase transition
• Revealing the non-adiabatic nature of dark energy perturbations from galaxy clustering data
• Spherical collapse and virialization in $f(T)$ gravities
• Viscous Chaplygin Gas Models as a Spherical Top-Hat Collapsing Fluids
• Non-linear dark matter collapse under diffusion
• Early-Matter-Like Dark Energy and the Cosmic Microwave Background