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 - E iso (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 z eff = 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 ω 0CDM and the ω 0 ω 1CDM 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 ω 0CDM 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 - E iso correlation with those from the prompt-afterglow emission LX - TX - Lp correlation.
Published Version
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