Tracing dark energy history with gamma ray bursts

Understand

Observations of gamma-ray bursts up to $z\sim 9$ are best suited to study the possible evolution of the Universe equation of state at intermediate redshifts.

• We apply the Combo-relation to a sample of 174 gamma ray bursts to investigate possible evidence of evolving dark energy parameter $w(z)$.
• We first build a gamma ray burst Hubble's diagram and then we estimate the set ($\Omega_m$, $\Omega_{\Lambda}$) in the framework of flat and non-flat $\Lambda$CDM paradigm.
• We then get bounds over the $w$CDM model, where $w$ is thought to evolve with redshift, adopting two priors over the Hubble constant in tension at $4.4$-$\sigma$, i.e.