On cosmology of interacting varying polytropic dark fluids

TL;DR

This paper explores models of the universe's accelerated expansion driven by a varying polytropic dark fluid interacting non-gravitationally with dark matter, using observational data and cosmographic analysis to constrain the models.

Contribution

It introduces new cosmological models with non-linear interactions between varying polytropic dark fluids and dark matter, analyzed through observational constraints and cosmographic methods.

Findings

Models can explain accelerated expansion with specific interaction types.

Observational data constrains model parameters effectively.

Non-gravitational interactions improve cosmological model fits.

Abstract

In this paper a possibility of the accelerated expansion of the large scale universe with a varying polytropic fluid of a certain type is presented. About a special role of non-gravitational interactions between dark energy and dark matter, in particular, about a possibility of improvement and solution of problems arising in modern cosmology, has been discussed for a long time. This motivates us to consider new models, where non-gravitational interactions between varying polytropic fluid and cold dark matter are allowed. Mainly non-linear interactions of a specific type is considered, found in recent literature. In order to understand the behavior of suggested cosmological models, besides cosmographic analysis, $Om$ analysis is applied. Moreover, with different datasets, including a strong gravitational lensing dataset, the observational constraints on the model parameters are obtained using $\chi^{2}$ analysis.