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Variable Polytropic gas cosmology

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Abstract

We mainly study a cosmological scenario represented by the variable Polytropic gas (VPG) unified energy density proposal. To reach this aim, we start with reconstructing a variable form of the original Polytropic gas (OPG) definition. We show that this model is a generalization of the OPG, cosmological constant plus cold dark matter (ΛCDM) and two different Chaplygin gas models. Later, we fit the auxiliary parameters given in the model and discuss essential cosmological features of the VPG proposal. Besides, we compare the VPG with the OPG by focusing on recent observational dataset given in literature including Planck 2018 results. We see that the VPG model yields better results than the OPG description and it fits very well with the recent experimental data. Moreover, we discuss some thermodynamical features of the VPG and conclude that the model describes a thermodynamically stable system.

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79 ASTRONOMY AND ASTROPHYSICSCOSMOLOGICAL CONSTANTCOSMOLOGYDATASETSENERGY DENSITYEXPERIMENTAL DATANONLUMINOUS MATTER

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2019-08-15. Variable Polytropic gas cosmology. https://doi.org/10.1016/j.aop.2019.04.011

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