Radiation Mechanism and Jet Composition of Gamma-Ray Bursts and GeV-TeV selected Radio Loud Active Galactic Nuclei

Abstract

Gamma-ray bursts (GRBs) and GeV-TeV selected radio loud Active Galactic Nuclei (AGNs) are compared based on our systematic modeling of the observed spectral energy distributions of a sample of AGNs with a single-zone leptonic model. We show that the correlation between the jet power (P_{jet}) and the prompt gamma-ray luminosity (L_{jet}) of GRBs is consistent, within the uncertainties, with the correlation between jet power and the synchrotron peak luminosity (L_{s, jet}) of flat spectrum radio quasars (FSRQs). Their radiation efficiencies (\varepsilon) are also comparable (>10% for most sources), which increase with the bolometric jet luminosity (L_{bol,jet}) for FSRQs and with the L_{jet} for GRBs with similar power-law indices. BL Lacs do not follow the P_{jet}-L_{s, jet} relation of FSRQs. They have lower \varepsilon and L_{bol, jet} values than FSRQs, and a tentative L_{bol, jet}-\varepsilon relation is also found, with a power-law index being different from that of the FSRQs. The magnetization parameters (\sigma) of FSRQs are averagely larger than that of BL Lacs. They are anti-correlated with $\varepsilon$ for the FSRQs, but positive correlated with \varepsilon for the BL Lacs. GeV Narrow-line Seyfert 1 galaxies potentially share similar properties with FSRQs. Based on the analogy between GRBs and FSRQs, we suggest that the prompt gamma-ray emission of GRBs is likely produced by synchrotron process in a magnetized jet with high radiation efficiency, similar to FSRQs. The jets of BL Lacs, on the other hand, are less efficient and are likely more matter dominated.