Viscous cosmological fluids and large-scale structure

TL;DR

This paper explores a viscous fluid cosmological model that can mimic the $mbda$CDM model, analyzing its background evolution, constraining parameters with supernova data, and studying its impact on large-scale structure formation.

Contribution

It derives the background equations for viscous interacting fluids and investigates linear perturbations, providing insights into structure disintegration in late-time universe.

Findings

Model mimics $mbda$CDM under certain conditions.

Constraints on cosmological parameters obtained from supernova data.

Predicts disintegration of large-scale structures in late universe.

Abstract

In this paper, we study the viscous fluid cosmological model that when certain conditions are invoked mimics the $\Lambda$CDM model. The background equations governing the evolution of viscous interacting fluids in a multifluid system are derived. The Markov Chain Monte Carlo (MCMC) simulation is applied to constrain the best-fit cosmological parameters with Supernova Type 1a data. In addition, linear cosmological perturbations are investigated in a dust-matter-dominated frame using a $1+3$ covariant formalism approach. It is evident from the perturbation results obtained that the model predicts the disintegration of bound structures of large-scale structures in the late-time universe.