Constraints on Cardassian universe from Gamma ray bursts

TL;DR

This paper uses gamma-ray burst data, combined with BAO and CMB observations, to constrain parameters of the Cardassian universe models, demonstrating GRBs as a viable observational tool.

Contribution

It provides new constraints on Cardassian models using GRB data calibrated to avoid circularity, combined with BAO and CMB data, which was not extensively done before.

Findings

GRBs can effectively constrain Cardassian models.

Best-fit parameters for the original Cardassian model are Ω_m0=0.27, n=0.06.

Best-fit parameters for the modified polytropic Cardassian model are Ω_m0=0.27, n=-0.09, β=0.82.

Abstract

Constraints on the original Cardassian model and the modified polytropic Cardassian model are examined from the recently derived 42 gamma-ray bursts (GRBs) data calibrated with the method avoiding the circularity problem. The results show that GRBs can be an optional observation to constrain on the Cardassian models. Combining the GRBs data with the newly derived size of baryonic acoustic oscillation peak from the Sloan Digital Sky Survey (SDSS), and the position of first acoustic peak of the Cosmic Microwave Background radiation (CMB) from Wilkinson Microwave Anisotropy Probe (WMAP), we find $\Omega_{m0}=0.27_{-0.02}^{+0.02}, n=0.06_{-0.08}^{+0.07}$ ($1\sigma$) for the original Cardassian model, and $\Omega_{m0}=0.27^{+0.03}_{-0.02}$, $n=-0.09_{-1.91}^{+0.23}, \beta=0.82_{-0.62}^{+2.10}$ ($1\sigma$) for the modified polytropic Cardassian model.