Spherical `Top-Hat' Collapse in general Chaplygin gas dominated universes

TL;DR

This paper extends the spherical top-hat collapse model to generalized Chaplygin gas universes, analyzing non-linear structure formation and the impact of model parameters on collapse dynamics.

Contribution

It introduces an exact formulation for effective sound speed and considers all energetic components, enhancing understanding of structure growth in gCg cosmologies.

Findings

Structure growth accelerates with higher lpha values.

The model provides a detailed non-linear analysis of collapse in gCg universes.

Effective sound speed is explicitly formulated for various parameters.

Abstract

We expand previous works on the spherical `top-hat' collapse (SC-TH) framework in generalized Chaplygin gas (gCg) dominated universes. Here we allow the collapse in all energetic components within the system. We analyze the non-linear stages of collapse for various choices of parameter \alpha of the gCg model introducing an exact formulation for the so-called effective sound speed, $c_{eff}^2$. We show that, within the SC-TH framework, the growth of the structure becomes faster with increasing values of \alpha.