Spherical “top-hat” collapse in general-Chaplygin-gas-dominated universes

Abstract

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