Radiation mechanism and jet composition of gamma-ray bursts and gev-tev-selected radio-loud active galactic nuclei

摘要

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 (ε) 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 Lac objects (BL Lacs) do not follow the P _(jet)-L _s, _(jet) relation of FSRQs. They have lower ε and L _(bol), jet values than FSRQs, and a tentative L _(bol), _(jet)-ε relation is also found, with a power-law index different from that of the FSRQs. The magnetization parameters (σ) of FSRQs are on average larger than that of BL Lacs. They are anti-correlated with ε for the FSRQs, but positively correlated with ε 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 the synchrotron process in a magnetized _(jet) with high radiation efficiency, similar to FSRQs. The _(jet)s of BL Lacs, on the other hand, are less efficient and are likely more matter-dominated.