Spherical Collapse for Viscous Generalized Chaplygin Gas Model

TL;DR

This paper investigates the nonlinear spherical collapse of viscous generalized Chaplygin gas, analyzing how model parameters affect structure formation and comparing results with the standard Lambda Cold Dark Matter model.

Contribution

It provides a detailed analysis of the nonlinear collapse in VGCG, highlighting the effects of viscosity and model parameters on structure formation, which is a novel focus in this context.

Findings

Smaller viscosity parameter $ $ accelerates collapse.

Larger $ $ delays structure formation.

VGCG collapse behavior closely resembles $DM$ when $ < 10^{-2}$.

Abstract

The nonlinear collapse for viscous generalized Chaplygin gas Model (VGCG) was analyzed in the framework of spherical top-hat collapse. As the VGCG and baryons are essential to form the large scale structure, we focused on their nonlinear collapse in this paper. We discussed the influence of model parameters $\alpha$ and $\zeta_{0}$ on the spherical collapse by varying their values and compare with $\Lambda CDM$. The results show that, for the VGCG model, smaller $\zeta_{0}$ and larger $\alpha$ make the structure formation earlier and faster, and the collapse curves of VGCG model is almost distinguished with the $\Lambda CDM$ model when the model parameter $\alpha$ is less than $10^{-2}$.