Cosmological constraints from calibrated Ep - E iso gamma-ray burst correlation by using DESI 2024 data release

Abstract

Recent outcomes by the DESI Collaboration have shed light on a possible slightly evolving dark energy, challenging the standard ΛCDM paradigm. To better understand dark energy nature, high-redshift observations like gamma-ray burst data become essential for mapping the universe expansion history, provided they are calibrated with other probes. To this aim, we calibrate the Ep - Eiso (or Amati) correlation through model-independent Bézier interpolations of the updated Hubble rate and the novel DESI data sets. More precisely, we provide two Bézier calibrations: i) handling the entire DESI sample, and ii) excluding the point at zeff = 0.51, criticized by the recent literature. In both the two options, we let the comoving sound horizon at the drag epoch, rd, vary in the range rd ∈ [138, 156] Mpc. The Planck value is also explored for comparison. By means of the so-calibrated gamma-ray bursts, we thus constrain three dark energy frameworks, namely the standard ΛCDM, the ω0CDM and the ω0ω1CDM models, in both spatially flat and non-flat universes. To do so, we worked out Monte Carlo Markov chain analyses, making use of the Metropolis-Hastings algorithm. Further, we adopt model selection criteria to check the statistically preferred cosmological model finding a preference towards the concordance paradigm with a zero curvature parameter. Nonetheless, the criteria also show a weak preference towards the non-flat ΛCDM and the flat ω0CDM scenario, leaving open to the possibility of such models as alternatives to the flat concordance paradigm. Finally, we compared the constraints got from the prompt emission Ep - Eiso correlation with those from the prompt-afterglow emission LX - TX - Lp correlation.