Jetted Active Galactic Nuclei

TL;DR

This paper reviews multi-wavelength observations of blazars, revealing how jet power, disk luminosity, and black hole mass are interconnected, and discusses the physical properties and formation of relativistic jets in active galactic nuclei.

Contribution

It provides a comprehensive synthesis of observational data and models, highlighting the relationships between jet power, accretion rate, and black hole characteristics in blazars.

Findings

Jet power correlates with accretion rate.

Jets are magnetically dominated at launch but become kinetically dominated.

Jets can be more powerful than the accretion disk luminosity.

Abstract

Most of the electromagnetic output of blazars (BL Lac objects and Flat Spectrum Radio Quasars) comes out in the gamma-ray band, making the Large Area Telescope [0.1-100 GeV] onboard the Fermi satellite and the Cherenkov telescopes crucial for gather crucial data and thus to understand their physics. These data are complemented by the observations of the Swift satellite in the X-ray and optical-UV bands, and by ground based optical and radio telescopes. This rich coverage of the spectrum allows a robust modelling, from which important trends start to emerge. In powerful sources we see the contribution of the accretion disk that, once modeled, give us the black hole mass and the accretion rate. Even when not directly visible, the disk luminosity can be derived through the broad emission lines. Therefore we start to know the jet power, the disk luminosity, and the black hole mass, 3 crucial ingredients if we want to draw a general scenario. At the start, jets are believed to be magnetically dominated. And yet, on the scale where they emit most of their luminosity, their power is already in the form of kinetic energy of particles. Relativistic jets are formed for a very broad range of the disk luminosity, from close to Eddington down to at least 1e-4 Eddington. Their power correlates with the accretion rate, and can be even more powerful than the accretion disk luminosity.