Modeling the Broad-Band Emission from the Gamma-Ray Emitting Narrow-Line Seyfert-1 Galaxies 1H 0323+342 and B2 0954+25A

Abstract

Prior to the Fermi-LAT era, only two classes of Active Galactic Nuclei (AGN) were thought to harbor relativistic jets that radiate up to gamma-ray energies: blazars and radio galaxies. The detection of variable gamma-ray emission from Narrow Line Seyfert 1 (NLSy1) galaxies has put them on the spotlight as a new class of gamma-ray emitting AGN. In this respect, gamma-ray emitting NLSy1s seem to be situated between blazars (dominated by non-thermal emission) and Seyferts (accretion disc dominated). In this work, we model the Spectral Energy Distribution (SED) of two gamma-loud NLSy1s, 1H 0323+342 and B2 0954+25A, during quiescent and flaring episodes via a multi-component radiative model that features a relativistic jet and external photon fields from the torus, disc, corona and Broad Line Region (BLR). We find that the interpretation of the high-energy emission of jetted NLSy1s requires taking into account Inverse Compton emission from particles in the relativistic jet that interact with external photon fields. Minimal changes are applied to the model parameters to transition from average to flaring states. In this scenario, the observed variability is explained mainly by means of changes in the jet density and Doppler factor.

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

“…This confirmed also the scaling laws by Heinz and Sunyaev [80], because it was possible to overlap the jet morphologies of the two objects with the proper scaling [156]. Other studies at different wavelengths are [157][158][159][160][161][162][163][164][165][166][167].…”

“…It is also worth noting that the search for NLS1s extended to anomalous objects, with uncertain classification. It was suggested that the γ-detected quasar B2 0954 + 25A (z = 0.712) [163,197] [200,201].…”

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

“…Finally, it is also worth noting the instances in which location of γ-ray emission in the same source changes in different epochs (Foschini et al 2008(Foschini et al , 2011aGhisellini et al 2013;Pacciani et al 2014;Ahnen et al 2015). The similarity of the non-thermal (likely jet-dominated) components of the SEDs of γ-NLS1s and FSRQs seems to suggest that similar processes (i.e., external-Compton dominated γ-ray emission) may be at work in both classes of sources (e.g., Abdo et al 2009a;Berton et al 2016;Arrieta-Lobo et al 2017). Currently, seven FSRQs have been detected by IACTs (Mirzoyan 2017;Mukherjee & VERITAS Collaboration 2017;Cerruti et al 2017;Ahnen et al 2015;Abeysekara et al 2015;Sitarek et al 2015;Aleksić et al 2011;H.E.S.S.…”

“…Finally, it is also worth noting the instances in which location of γ-ray emission in the same source changes in different epochs (Foschini et al 2008(Foschini et al , 2011aGhisellini et al 2013;Pacciani et al 2014;Ahnen et al 2015). The similarity of the non-thermal (likely jet-dominated) components of the SEDs of γ-NLS1s and FSRQs seems to suggest that similar processes (i.e., external-Compton dominated γ-ray emission) may be at work in both classes of sources (e.g., Abdo et al 2009a;Berton et al 2016;Arrieta-Lobo et al 2017) MAGIC Collaboration et al 2008; also see TeVCat 5 for further references). A significant detection of γ-NLS1 by CTA at E 100 GeV would then lead to similar conclusions about the location of the γ-ray emission region, i.e., near the outer edge of the BLR.…”

High-energy neutrinos and gamma rays from the AGN-driven wind in NGC 1068

“…Building on previous work [22,23], we utilize a numerical code for modeling the multimessenger (photon and neutrino) emission resulting from a population of accelerated protons and electrons that are injected into a magnetized region and interact with ambient radiation fields and matter. The emission region is a sphere of radius R with a randomly-oriented magnetic field of amplitude B, through which plasma is flowing with velocity v. It is permeated by an external radiation field that serves as target photons for γγ as well as pγ interactions, with a spectrum characteristic of an accretion disk plus hot corona system around a black hole (BH) of mass M BH , total luminosity L disk , and fractional luminosity f cor for the corona [24], and intensity diluted according to the distance z from the BH. It also contains gas with density n g as the target for pp interactions, for which we follow the parameterization of Kelner et al [25].…”