Spherical collapse in coupled quintessence with a $\Lambda$CDM background

Understand

In this work we study the growth of cold dark matter density perturbations in the nonlinear regime on a conformally coupled quintessence model in which the background is designed to mimic a $\Lambda$CDM cosmology.

• The spherical collapse of overdense regions is analyzed.
• We highlight the role of the coupling on the overall dynamics, trace the evolution of the density contrast throughout the cosmic history and compute perturbative parameters such as the critical density contrast.
• We find that the coupling has the influence of delaying the collapse due to the slower growth of matter perturbations.