Abstract
We explore a unified model of dark matter and dark energy. This new model is a generalization of the generalized Chaplygin gas model and is known as a new generalized Chaplygin gas (NGCG) model. We study the evolutions of the Hubble parameter and the distance modulus for the model under consideration and the standard ΛCDM model and compare that with the observational datasets. Furthermore, we demonstrate two geometric diagnostics analyses including the statefinder (r,s) and Om(z) to the discriminant NGCG model from the standard ΛCDM model. The trajectories of evolution for (r,s) and Om(z) diagnostic planes are shown to understand the geometrical behavior of the NGCG model by using different observational data points.
Highlights
Cosmic observations [1,2] indicate that the expansion of the Universe is accelerating at the present time
We have shown the evolutionary trajectories of another statefinder pair (q, r) for the new generalized Chaplygin gas (NGCG) model in Figure 4 for the best-fit values of model parameters, as given in Table 1, arising from the joint analysis of the H(z) + BAO + CMB + BBN + SNIa (Pantheon) dataset
We have examined a new generalized Chaplygin gas (NGCG) model
Summary
Cosmic observations [1,2] indicate that the expansion of the Universe is accelerating at the present time. Salahedin et al [37] obtained tight constraints on the the free parameters of NGCG model based on the statistical Markov Chain Monte Carlo (MCMC) method by using different combinations of the latest data samples They showed that the big tension between the high- and low-redshift observations appearing in the ΛCDM model to predict the present value of Hubble constant H0 can be alleviated in the NGCG model. In this context, it should be mentioned here that, using various updated observational datasets, recently Yang et al [38,39] investigated unified dark fluid models based on CG cosmologies. The symbol overhead dot indicates a derivative with respect to the cosmic time t, the symbol prime indicates a derivative with respect to the scale factor (a), and a subscript zero refers to any quantity calculated at the present time
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