Distributions of Gamma-Ray Bursts and Blazars in the $L_{ m p}-E_{ m p}$ Plane and Possible Implications for their Radiation Physics

摘要

We present a spectral analysis for a sample of redshift known GRBs observedwith {\em Fermi}/GBM. Together with the results derived from our systematicalspectral energy distribution modeling with the leptonic models for a {\emFermi}/LAT blazar sample, we compare the distributions of the GRBs and theblazars by plotting the synchrotron peak luminosity ($L_{\rm s}$) and thecorresponding peak photon energy $E_{\rm s}$ of blazars in the $L_{\rmp}-E_{\rm p}$ plane of GRBs, where $L_{\rm p}$ and $E_{\rm p}$ are the peakluminosity and peak photon energy of the GRB time-integrated $\nu f_\nu$spectrum, respectively. The GRBs are in the high-$L_{\rm p}$, high-$E_{\rm p}$corner of the plane and a tight $L_{\rm p}-E_{\rm p}$ relation is found, i.e.,$L_{\rm p}\propto E_{\rm p}^{2.13^{+0.54}_{-0.46}}$. Both FSRQs and LBLs areclustered in the low-$E_{\rm p}$, low-$L_{\rm p}$ corner. IBLs and HBLs have$E_{\rm s}\sim 2\times 10^{-3} - 10^{2}$ keV and $L_{\rm s} \sim 10^{44} -10^{47}$ erg s$^{-1}$, but no dependence of $L_{\rm s}$ on $E_{\rm s}$ isfound. We show that the tight $L_p-E_p$ relation of GRBs is potentiallyexplained with the synchrotron radiation of fast-cooling electrons in a highlymagnetized ejecta, and the weak anti-correlation of $L_{\rm s}-E_{\rm s}$ forFSRQs and LBLs may be attributed to synchrotron radiation of slow-coolingelectrons in a moderately magnetized ejecta. The distributions of IBLs and HBLsin the $L_{\rm p}-E_{\rm p}$ plane may be interpreted with synchrotronradiation of fast-cooling electrons in a matter-dominated ejecta. These resultsmay present a unified picture for the radiation physics of relativistic jets inGRBs and blazars within the framework of the leptonic synchrotron radiationmodels.