The Collimation‐corrected Gamma‐Ray Burst Energies Correlate with the Peak Energy of Their ν<i>F</i>_νSpectrum

TLDR

The study focuses on gamma‑ray bursts with known redshift and observed peak energy. The authors aim to use the correlation between collimation‑corrected energy and peak energy to understand prompt GRB emission mechanisms and to assess its potential as a cosmological tool. They estimate jet opening angles from afterglow light‑curve breaks and compute the collimation‑corrected energy Eγ for each burst. They find that Eγ spans two orders of magnitude and correlates tightly with the source‑frame peak energy as Eγ^0.7, suggesting a small scatter that could enable cosmological applications.

Abstract

We consider all bursts with known redshift and $νF_ν$ peak energy, $E^{obs}_{peak}$. For a good fraction of them an estimate of the jet opening angle is available from the achromatic break of their afterglow light curve. This allows the derivation of the collimation--corrected energy of the bursts, $E_γ$. The distribution of the values of $E_γ$ is more spread with respect to previous findings, covering about two orders of magnitude. We find a surprisingly tight correlation between $E_γ$ and the source frame $E_{peak}$: $E^{obs}_{peak}(1+z) \propto E_γ^{0.7}$. This correlation can shed light on the still uncertain radiation processes for the prompt GRB emission. More importantly, if the small scatter of this newly found correlation will be confirmed by forthcoming data, it will be possible to use it for cosmological purposes.