A Panchromatic View of Relativistic Jets in Narrow-Line Seyfert 1 Galaxies

Abstract

Abstract:The discovery by the Large Area Telescope on board Fermi of variable γ-ray emission from radio-loud narrow-line Seyfert 1 (NLSy1) galaxies revealed the presence of a possible third class of Active Galactic Nuclei (AGN) with relativistic jets in addition to blazars and radio galaxies. Considering that NLSy1 are usually hosted in spiral galaxies, this finding poses intriguing questions about the nature of these objects and the formation of relativistic jets. We report on a systematic investigation of the γ-ray properties of a sample of radio-loud NLSy1, including the detection of new objects, using 7 years of Fermi-LAT data with the new Pass 8 event-level analysis. In addition we discuss the radio-to-very-high-energy properties of the γ-ray emitting NLSy1, their host galaxy, and black hole mass in the context of the blazar scenario and the unification of relativistic jets at different scales.

Prospects for gamma-ray observations of narrow-line Seyfert 1 galaxies with the Cherenkov Telescope Array

“…Following the first detection of a NLS1 in γ-rays (E > 100 MeV) by Fermi-LAT (PMN J0948+0022, Abdo et al 2009a;Foschini et al 2010;Abdo et al 2009b) a new subclass of NLS1s was defined, the γ-ray emitting NLS1 (γ-NLS1) galaxies, now consisting of about 20 objects, as sources whose overall observational properties are strongly reminiscent of those of jetted sources (see, e.g. Foschini 2012;Foschini et al 2015;D'Ammando et al 2016a). Currently, however, no detection has been obtained in the very high energy (VHE, E > 50 GeV) regime (Whipple upper limit (UL) on 1H 0323+342, Falcone et al 2004 In Romano et al (2018) (Paper I) we considered the prospects for observations of γ-NLS1 as a class of sources to investigate with the Cherenkov Telescope Array (CTA) since the detection in the VHE regime would provide important clues on the location of the γ-ray emitting region.…”

Relativistic Jets from AGN Viewed at Highest Angular Resolution

“…The accumulation of MWL data on γ-ray NLSy1s reveals that their broadband SEDs are similar to those of FSRQ [219,220], where the overall radiation output is dominated by the inverse Compton component. This indicates the presence of strong external seed photon fields, most likely from the broad-line region or dusty torus illuminated by the luminous accretion flows.…”

GeV gamma-ray narrow-line Seyfert 1 galaxies and the Fermi LAT Flare Advocate service

“…In the gamma-ray photon index vs luminosity plane, gamma-ray jetted NLSy1 galaxies lie in the plane region occupied by FSRQs, with the exception of 1H 0323+342, RX J1644.7+2619 and SBS 0846+513. These cited NLSy1 galaxies, however, have the lowest redshift and this might be the reason why their gamma-ray luminosity is lower than the other NLSy1 and FSRQ [29]. The strongest gamma-ray outbursts observed from SBS 0846+513, PMN J0948+0022, PKS 1502+036, and 1H 0323+342 reached a peak of apparent isotropic gamma-ray luminosity of 10 47 −10 48 erg s −1 , comparable to that of some bright and powerful FSRQs, except for the main outburst episodes of FSRQs.…”