Gamma-ray emission from Narrow-Line Seyfert 1 Galaxies and implications on the jets unification

TL;DR

This paper discusses the discovery of gamma-ray emissions from Narrow-Line Seyfert 1 Galaxies, highlighting their significance as a new class of active galactic nuclei with relativistic jets, and compares them to other jet systems.

Contribution

It introduces NLS1s as a new gamma-ray emitting class of AGN and explores their properties and similarities with other jet systems.

Findings

NLS1s are confirmed as a new gamma-ray emitting AGN class.

NLS1s have low masses (10^6-8 Msun) and high accretion rates.

NLS1s show similarities to Galactic compact objects in jet emission.

Abstract

The recent discovery by Fermi/LAT of high-energy (E>100 MeV) gamma rays from Narrow-Line Seyfert 1 Galaxies (NLS1s) made evident the existence of a third class of gamma-ray emitting Active Galactic Nuclei (AGN), after blazars and radio galaxies. It is now possible to study a rather unexplored range of low masses (10^6-8 Msun) and high accretion rates (up to the Eddington limit) of AGN with relativistic jets. A comparison with the jet emission from Galactic compact objects shows some striking similarities, indicating that NLS1s are the low-mass counterpart of blazars as neutron stars are the low-mass jet systems analogue of stellar mass black holes.