Accretion and jet power in active galactic nuclei

TL;DR

This paper reexamines the relationship between radio loudness, jet power, and black hole properties in active galactic nuclei, incorporating new data on relativistic jets in Narrow-Line Seyfert 1 Galaxies and comparing them to other compact objects.

Contribution

It introduces a revised analysis of jet power mechanisms in AGN, highlighting the limitations of the Blandford-Znajek model and proposing a composite jet scenario.

Findings

Blandford-Znajek mechanism explains BL Lac jet power but not quasars or NLS1s.

NLS1s are analogous to low-mass black hole systems like neutron stars.

A composite jet model with magnetospheric and hydromagnetic components is favored.

Abstract

The classical diagrams of radio loudness and jet power as a function of mass and accretion rate of the central spacetime singularity in active galactic nuclei are reanalyzed by including the data of the recently discovered powerful relativistic jets in Narrow-Line Seyfert 1 Galaxies. The results are studied in the light of the known theories on the relativistic jets, indicating that while the Blandford-Znajek mechanism is sufficient to explain the power radiated by BL Lac Objects, it fails to completely account the power from quasars and Narrow-Line Seyfert 1. This favors the scenario outlined by Cavaliere & D'Elia of a composite jet, with a magnetospheric core plus a hydromagnetic component emerging as the accretion power increases and the disc becomes radiation-pressure dominated. A comparison with Galactic compact objects is also performed, finding some striking similarities, indicating that as the neutron stars are the low-mass jet systems analogue of black holes, the Narrow-Line Seyfert 1 Galaxies are the low-mass counterpart of the blazars.