Revisiting the Spectral-Energy Correlations of GRBs with it Fermi Data I: Model-wise Properties

Revisiting the Spectral-Energy Correlations of GRBs with it Fermi Data I: Model-wise Properties by Liang Li. on Tuesday 22 November Gamma-ray bursts (GRBs) exhibit a diversity of spectra. Several spectral models (e.g., Band, cutoff power-law, and blackbody) and their hybrid versions (e.g., Band+blackbody) have been widely used to fit the observed GRB spectra. Here, we collect all the bursts detected by {\it Fermi}-GBM with known redshifts from July 2008 to May 2022, motivated to achieve a ``clean" model-based GRB spectral-energy correlation analysis. A nearly complete GRB sample was created, containing 153 such bursts. Using the sample and by performing detailed spectral analysis and model comparisons, we investigate the cosmological rest-frame peak energy ($E_{\rm p,z}$) of the $\nu F_\nu$ prompt emission spectrum correlated with (i) the isotropic-bolometric-equivalent emission energy $E_{\gamma, \rm iso}$ (the Amati relation), and (ii) the isotropic-bolometric-equivalent peak luminosity $L_{\rm p, iso}$ (the Yonetoku relation). From a linear regression analysis, a tight correlation between $E_{\rm p,z}$ and $E_{\gamma, \rm iso}$ (and $L_{\gamma,\rm iso}$) is found for both the Band-like and CPL-like bursts. The correlations take the form of $E_{\rm p,z} \propto E^{0.41\pm0.06}_{\gamma, \rm iso}$ for our Band-like bursts (sGRBs+lGRBs) and of $E_{\rm p,z} \propto E^{0.00\pm0.13}_{\gamma, \rm iso}$ for the CPL-like bursts (sGRBs+lGRBs) in the $E_{\rm p,z}$-$E_{\gamma,\rm iso}$ plane. Similar results are also found in the $E_{\rm p,z}$-$L_{\gamma,\rm iso}$ plane, which take the form of $E_{\rm p,z} \propto L^{0.41\pm0.09}_{\rm p, iso}$ for the whole Band-like bursts and $E_{\rm p,z} \propto L^{0.29\pm0.05}_{\rm p, iso}$ for the full CPL-like bursts. More interestingly, the CPL-like bursts do not fall on the Band-like burst Amati and Yonetoku correlations, suggesting distinct radiation processes, and pointing towards the fact that these spectral-energy correlations are tightly reliant on the model-wise properties. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.12187v1