Broad Line Radio Galaxies Observed with Fermi-LAT: The Origin of the GeV Gamma-Ray Emission

Abstract

We report on a detailed investigation of the gamma-ray emission from 18 broad line radio galaxies (BLRGs) based on two years of Fermi Large Area Telescope (LAT) data. We confirm the previously reported detections of 3C 120 and 3C 111 in the GeV photon energy range; a detailed look at the temporal characteristics of the observed gamma-ray emission reveals in addition possible flux variability in both sources. No statistically significant gamma-ray detection of the other BLRGs was however found in the considered dataset. Though the sample size studied is small, what appears to differentiate 3C 111 and 3C 120 from the BLRGs not yet detected in gamma-rays is the particularly strong nuclear radio flux. This finding, together with the indications of the gamma-ray flux variability and a number of other arguments presented, indicate that the GeV emission of BLRGs is most likely dominated by the beamed radiation of relativistic jets observed at intermediate viewing angles. In this paper we also analyzed a comparison sample of high accretion-rate Seyfert 1 galaxies, which can be considered radio-quiet counterparts of BLRGs, and found none were detected in gamma-rays. A simple phenomenological hybrid model applied for the broad-band emission of the discussed radio-loud and radio-quiet type 1 active galaxies suggests that the relative contribution of the nuclear jets to the accreting matter is > 1 percent on average for BLRGs, whilst <0.1 percent for Seyfert 1 galaxies.

18 pages, 9 figures, accepted for publication in the ApJ

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Cited by in corpus (58)

• The Second Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
• The Third Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
• SBS 0846+513: a new gamma-ray emitting Narrow-Line Seyfert 1 galaxy
• Diffuse $\gamma$-ray emission from misaligned active galactic nuclei
• Radio-emitting narrow-line Seyfert 1 galaxies in the JVLA perspective
• An X-Ray View of the Jet-Cycle in the Radio Loud AGN 3C120
• Core shifts, magnetic fields and magnetization of extragalactic jets
• Search for Gamma-ray Emission from X-ray Selected Seyfert Galaxies with Fermi-LAT
• The Extragalactic Gamma-ray Sky in the Fermi era
• The gamma-ray emission region in the FRII Radio Galaxy 3C 111
• First detection in gamma-rays of a young radio galaxy: Fermi-LAT observations of the Compact Symmetric Object PKS 1718-649
• Collective Evidence for Inverse Compton Emission from External Photons in High-Power Blazars
• Comparison of ejection events in the jet and accretion disc outflows in 3C 111
• The Nature of the Stable Soft X-ray Emissions in Several Types of Active Galactic Nuclei Observed by Suzaku
• Six Years of Fermi-LAT and Multi-wavelength Monitoring of the Broad-Line Radio Galaxy 3C 120: Jet Dissipation at Sub-parsec Scales from the Central Engine
• Jet Emission in Young Radio Sources: a Fermi-LAT Gamma-ray View
• Radio Galaxies Dominate the High-Energy Diffuse Gamma-Ray Background
• Baryon Loading Efficiency and Particle Acceleration Efficiency of Relativistic Jets: Cases For Low Luminosity BL Lacs
• Suzaku Observations of gamma-Ray Bright Radio Galaxies: Origin of the X-ray Emission and Broad-Band Modelin
• Multiwavelength Astronomy and CTA: X-rays
• The column density distribution of hard X-ray radio galaxies
• Comparing 3C 120 jet emission at small and large scales
• Jet Properties of Compact Steep-Spectrum Sources and an Eddington-Ratio-Driven Unification Scheme of Jet Radiation in Active Galactic Nuclei
• Discovery of gamma-ray emission from the Broad Line Radio Galaxy Pictor A
• Comparison of hard X-ray spectra of luminous radio galaxies and their radio-quiet counterparts
• NuSTAR hard X-ray spectra of radio galaxies
• Unveiling the nature of the gamma-ray emitting AGN PKS 0521-36
• Radio/X-ray monitoring of the broad-line radio galaxy 3C 382. High-energy view with XMM-Newton and NuSTAR
• An outburst scenario for the X-ray spectral variability in 3C 111
• Fermi-LAT and Suzaku Observations of the Radio Galaxy Centaurus B
• Spectroscopic classification, variability and SED of the Fermi-detected CSS 3C 286: the radio-loudest NLS1 galaxy?
• The High Energy view of the Broad Line Radio Galaxy 3C 111
• Nonthermal radiation from the central region of super-accreting active galactic nuclei
• Examining High Energy Radiation Mechanisms of Knots and Hotspots in Active Galactic Nucleus Jets
• HST emission-line images of nearby 3CR radio galaxies: two photoionization, accretion and feedback modes
• Comparison of SEDs of very massive radio-loud and radio-quiet AGN
• On the gamma-ray emission from 3C 120
• Application of the spine-layer jet radiation model to outbursts in the broad-line radio galaxy 3C 120
• The Composition and Power of the Jet of the Broad-Line Radio Galaxy 3C 120
• Feeding and feedback in the powerful radio galaxy 3C 120
• The nature of the multi-wavelength emission of 3C 111
• Signatures of the disk-jet coupling in the Broad-line Radio Quasar 4C+74.26
• General Physical Properties of Gamma-Ray-emitting Radio Galaxies
• Faint $\gamma$-ray sources at low-redshift: the radio galaxy IC 1531
• Discovery of gamma-ray emission from a strongly lobe-dominated quasar 3C 275.1
• The composite X-ray spectrum of 3CRR Quasars
• Cross-match between the latest Swift-BAT and Fermi-LAT catalogs
• An XMM-Newton View of the Radio Galaxy 3C 411
• TXS 1433+205: The most distant gamma-ray emitting FR II radio galaxy
• Broad-band X-ray observation of broad-line radio galaxy 3C 109
• Multiwavelength study of radio galaxy Pictor A: detection of western hotspot in far-UV and possible origin of high energy emissions
• Revisiting Correlations Between Broad-Line and Jet Emission Variations for AGNs: 3C 120 and 3C 273
• Hints of correlation between broad-line and radio variations for 3C 120
• Excess Galactic molecular absorption toward the radio galaxy 3C 111
• Gamma-ray emission in radio galaxies, from MeV to TeV
• Complex Structure of the Eastern Lobe of the Pictor A Radio Galaxy: Spectral Analysis and X-ray/Radio Correlations
• XMM-Newton spectrum of the radio-loud quasar 3C 215: slim accretion disk or SMBH binary?
• IGR J18249-3243: a new GeV-emitting FR II and the emerging population of high energy radio galaxies