$L_{\rm syn}-E_{\rm syn, p}-\delta$ relation in Active Galactic Nucleus Jets and Implication for the physical origin of the $L_{\rm p}-E_{\rm p,z}-\Gamma_0$ relation of Gamma-Ray Bursts

TL;DR

This study investigates the relation between jet radiations in AGNs and GRBs, revealing distinct correlations and suggesting jet power and radiation physics as key factors in their emission properties.

Contribution

It introduces a new tight relation between synchrotron luminosity, peak energy, and Doppler factor in AGNs, contrasting with GRB relations, highlighting different jet physics.

Findings

AGNs do not follow the GRB $L_{p}-E_{p,z}-\Gamma_0$ relation.

A tight $L_{syn} \propto E_{syn,p}^{0.45} \delta^{3.50}$ relation is found for FSRQs and NLS1s.

Doppler boosting explains the $L_{syn}$-$\delta$ dependence in AGNs, but not in GRBs.

Abstract

High energy photon radiations of gamma-ray bursts (GRBs) and active galactic nuclei (AGNs) are dominated by their jet radiations. We examine wether the synchrotron radiations of jets in BL Lacs, flat spectrum radio quasars (FSRQs), and Narrow Line Seyfert 1 galaxies (NLS1s) follow the relation between the prompt gamma-ray emission and the initial Lorentz factor ($\Gamma_0$) of GRBs. It is showed that the AGNs sample does not agree with the $L_{\rm p}-E_{\rm p,z}-\Gamma_{0}$ of GRBs. In addition, we obtain a tight relation of $L_{\rm syn}\propto E^{0.45\pm0.15}_{\rm syn,p}\delta^{3.50\pm0.25}$ for FSRQs and NLS1 galaxies, where $L_{\rm syn}$ is the luminosity at peak photon energy $E_{\rm syn, p}$ of the synchrotron radiations. This relation is different from the $L_{\rm p}-E_{\rm p,z}-\Gamma_{0}$ relation of GRBs. The dependence of $L_{\rm syn}$ to $\delta$ is consistent with the expectation of the Doppler boosting effect for the FSRQs and NLS1 galaxies, but it is not for GBRs. We argue that $\Gamma_0$ may be a representative of the kinetic power of the radiating region and the tight $L_{\rm p}-E_{\rm p, z}-\Gamma_0$ relation is shaped by the radiation physics and the jet power together.