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Jetted Narrow-Line Seyfert 1 Galaxies & Co.: Where Do We Stand?

Authors :
Luigi Foschini
Source :
Universe, Vol 6, Iss 9, p 136 (2020)
Publication Year :
2020
Publisher :
MDPI AG, 2020.

Abstract

The discovery in 2008 of high-energy gamma-rays from Narrow-Line Seyfert 1 Galaxies (NLS1s) made it clear that there were active galactic nuclei (AGN) other than blazars and radio galaxies that can eject powerful relativistic jets. In addition to NLS1s, the great performance of the Fermi Large Area Telescope made it possible to discover MeV-GeV photons emitted from more classes of AGN, like Seyferts, Compact Steep Spectrum Gigahertz Peaked Sources (CSS/GPS), and disk-hosted radio galaxies. Although observations indicate a variety of objects, their physical characteristics point to a central engine powered by a relatively small-mass black hole (but, obviously, there are interpretations against this view). This essay critically reviews the literature published on these topics during the last eight years and analyzes the perspectives for the forthcoming years.

Details

Language :
English
ISSN :
22181997
Volume :
6
Issue :
9
Database :
Directory of Open Access Journals
Journal :
Universe
Publication Type :
Academic Journal
Accession number :
edsdoj.f862ff10dc4d45b63a45236ec80b0f
Document Type :
article
Full Text :
https://doi.org/10.3390/universe6090136