Cosmological constrains on new generalized Chaplygin gas model

Abstract

We use different combinations of data samples to investigate the new generalized Chaplygin gas (NGCG) model in the context of dark energy (DE) cosmology. Using the available cosmological data, we put constraints on the the free parameters of NGCG model based on the statistical Markov chain Monte Carlo method. We then find the best fit values of cosmological parameters and those confidence regions in NGCG cosmology. Our result for the matter density parameter calculated in NGCG model is in excellent agreement with that of the standard CDM cosmology. We also find that the equation of state of DE of the model slightly favors the phantom regime. We show that the big tension between the lowand high-redshift observations appearing in CDM universe to predict the Hubble constant H 0 can be alleviated in NGCG model. However, from the statistical point of view, our results show that the standard CDM model fits the observations better than the NGCG cosmology.

Statefinder and Om Diagnostics for New Generalized Chaplygin Gas Model

“…Therefore, we require the minimizing of the sum of all the χ 2 functions in order to find the best fit values of free parameters. In a recent work, Salahedin et al [37] obtained the observational constraints on the free parameters of the present model by using different observational data samples including type Ia supernovae (SNIa) from the Union 2.1 [41] catalog and the Pantheon [42] catalog, Baryon acoustic oscillation (BAO), Big Bang nucleosynthesis (BBN) [43], and the Cosmic microwave background (CMB) from the results of WMAP observations and observational Hubble parameter data H(z) obtained from cosmic chronometers (for a detailed discussion, see Ref. [37] and the references therein).…”

“…In a recent work, Salahedin et al [37] obtained the observational constraints on the free parameters of the present model by using different observational data samples including type Ia supernovae (SNIa) from the Union 2.1 [41] catalog and the Pantheon [42] catalog, Baryon acoustic oscillation (BAO), Big Bang nucleosynthesis (BBN) [43], and the Cosmic microwave background (CMB) from the results of WMAP observations and observational Hubble parameter data H(z) obtained from cosmic chronometers (for a detailed discussion, see Ref. [37] and the references therein). By combining all data samples, Salahedin et al [37] performed a likelihood analysis based on the statistical MCMC algorithm to calculate the minimum of χ 2 and the best fit values of the cosmological parameters.…”

“…[37] and the references therein). By combining all data samples, Salahedin et al [37] performed a likelihood analysis based on the statistical MCMC algorithm to calculate the minimum of χ 2 and the best fit values of the cosmological parameters. Firstly, they combined the SNIa (Pantheon) with H(z), BAO, CMB, and BBN data and, secondly, they combined the SNIa (Union 2.1) with H(z), BAO, CMB, and BBN data.…”

“…Furthermore, the authors of [35,36] have also performed the statistical likelihood analysis using different datasets on the NGCG model and found some discrimination between the NGCG model and other DE models. In a recent work, 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 also 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 H 0 can be alleviated in the NGCG model.…”

“…Based on the Ref. [37], in this paper, we will extend the analysis on the NGCG model by performing the statefinder and O m diagnostic analysis to differentiate the NGCG model from the standard ΛCDM model and other DE models. Furthermore, we study the evolutions of the Hubble parameter and the distance modulus for the present model and the ΛCDM model and compare that with the observational datasets.…”