FERMIMONITORING OF RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES

Abstract

We present detailed analysis of the γ-ray flux variability and spectral properties of the five radio-loud narrow line Seyfert 1 (RL-NLSy1) galaxies, detected by the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope, namely 1H 0323+342, SBS 0846+513, PMN J0948+0022, PKS 1502+036, and PKS 2004−447. The first three sources show significant flux variations, including the rapid variability of a few hours by 1H 0323+342. The average γ-ray spectrum of 1H 0323+342 and PMN J0948+0022 shows deviation from a simple power-law (PL) behavior, whereas the PL model gives a better fit for the other three sources. The spectra of 1H 0323+342, SBS 0846+513, and PMN J0948+0022, which are in low, flaring, and moderately active states, respectively, show significant curvature. Such curvature in the γ-ray spectrum of 1H 0323+342 and PMN J0948+0022 could be due to the emission region located inside the broad line region (BLR) where the primary mechanism of the γ-ray emission is inverse-Compton (IC) scattering of BLR photons occurring in the Klein-Nishina regime. The γ-ray emission of SBS 0846+513 is explained by IC scattering of dusty torus photons, which puts the emission region outside the BLR and thus under the Thomson regime. Therefore, the observed curvature of SBS 0846+513 could be intrinsic to the particle energy distribution. The presence of curvature in the γ-ray spectrum and flux variability amplitudes of some of the RL-NLSy1 galaxies suggests that these sources could be akin to low/moderate jet power flat spectrum radio quasars.

Mapping the Narrow-Line Seyfert 1 Galaxy 1H 0323342+

“…The jet width at the convergence is 0.39 ± 0.17 mas [5], corresponding to ∼ 0.47 pc (or 4.5 × 10 5 r g ). The fastest variability at high-energy γ rays was measured to be ∼ 3.1 hours [32], which implies a size of the emitting region r < τ cδ/(1 + z) ∼ 1.8 × 10 15 cm. This is clearly too small for the jet size at the convergence shock.…”

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

“…Focusing on specific frequencies, the search for new detections at high-energies γ rays continued as the Fermi dataset increases [196,252], as well as monitoring or reanalysis of LAT data [253][254][255]. As already noted, presently the sample of firm γ-ray detections is composed of about two dozens of NLS1s [92,127], although reclassification of known γ-detected AGN has a great potentiality (e.g., [87]).…”

A Catalog of Narrow Line Seyfert 1 Galaxies from the Sloan Digital Sky Survey Data Release 12

“…It is important to find more radio-loud NLSy1 galaxies, due to the discovery of γ-ray emission in halfa-dozen of them by Fermi, which argues for the presence of relativistic jets in these sources (e.g. see, Paliya et al 2015). With an aim to find more radio-loud NLSy1 galaxies, we cross-correlated our sample with the FIRST survey (Catalog version 14dec17 † † ) within a search radius of 2 .…”