Fermi Large Area Telescope View of the Core of the Radio Galaxy Centaurus A

Abstract

We present gamma-ray observations with the LAT on board the Fermi Gamma-Ray Telescope of the nearby radio galaxy Centaurus~A. The previous EGRET detection is confirmed, and the localization is improved using data from the first 10 months of Fermi science operation. In previous work, we presented the detection of the lobes by the LAT; in this work, we concentrate on the gamma-ray core of Cen~A. Flux levels as seen by the LAT are not significantly different from that found by EGRET, nor is the extremely soft LAT spectrum ($\G=2.67\pm0.10_{stat}\pm0.08_{sys}$ where the photon flux is $Φ\propto E^{-\G}$). The LAT core spectrum, extrapolated to higher energies, is marginally consistent with the non-simultaneous HESS spectrum of the source. The LAT observations are complemented by simultaneous observations from Suzaku, the Swift Burst Alert Telescope and X-ray Telescope, and radio observations with the Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry (TANAMI) program, along with a variety of non-simultaneous archival data from a variety of instruments and wavelengths to produce a spectral energy distribution (SED). We fit this broadband data set with a single-zone synchrotron/synchrotron self-Compton model, which describes the radio through GeV emission well, but fails to account for the non-simultaneous higher energy TeV emission observed by HESS from 2004-2008. The fit requires a low Doppler factor, in contrast to BL Lacs which generally require larger values to fit their broadband SEDs. This indicates the $\g$-ray emission originates from a slower region than that from BL Lacs, consistent with previous modeling results from Cen~A. This slower region could be a slower moving layer around a fast spine, or a slower region farther out from the black hole in a decelerating flow.

Accepted by ApJ. 32 pages, 5 figures, 2 tables. J. Finke and Y. Fukazawa corresponding authors

References in corpus (36)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, and Basic Results
• Fermi Large Area Telescope Bright Gamma-ray Source List
• Bright AGN Source List from the First Three Months of the Fermi Large Area Telescope All-Sky Survey
• Sub-milliarcsecond Imaging of Quasars and Active Galactic Nuclei III. Kinematics of Parsec-Scale Radio Jets
• The 105 month Swift-BAT all-sky hard X-ray survey
• DiFX: A software correlator for very long baseline interferometry using multi-processor computing environments
• Fast variability of TeV gamma-rays from the radio galaxy M 87
• Synchrotron Self-Compton Analysis of TeV X-ray Selected BL Lacertae Objects
• Fermi Gamma-ray Imaging of a Radio Galaxy
• Implications of very rapid TeV variability in blazars
• Production of TeV gamma-radiation in the vicinity of the supermassive black hole in the giant radiogalaxy M87
• High-energy particle acceleration at the radio-lobe shock of Centaurus A
• The central parsecs of Centaurus A: High Excitation Gas, a Molecular Disk, and the Mass of the Black Hole
• High-energy Particle Acceleration and Production of Ultra-high-energy Cosmic Rays in the Giant Lobes of Centaurus A
• Ultra High Energy Cosmic Rays from Black Hole Jets of Radio Galaxies
• Resolving the innermost parsec of Centaurus A at mid-infrared wavelengths
• The Discovery of Cepheids and a Distance to NGC 5128
• A revised catalogue of EGRET gamma-ray sources
• Chandra and XMM-Newton Observations of the Nucleus of Centaurus A
• Observation of gamma-ray emission from the galaxy M87 above 250 GeV with VERITAS
• Galaxy Clusters in the Swift/BAT era: Hard X-rays in the ICM
• BAT X-ray Survey - III: X-ray Spectra and Statistical Properties
• New results on particle acceleration in the Centaurus A jet and counterjet from a deep Chandra observation
• A synchrotron self-Compton scenario for the very high energy gamma-ray emission of the radiogalaxy M87
• The Parsec-Scale Jets of the TeV Blazars H 1426+428, 1ES 1959+650, and PKS 2155-304: 2001-2004
• High energy radiation from Centaurus A
• The Suzaku Observation of the Nucleus of the Radio-Loud Active Galaxy Centaurus A: Constraints on Abundances of the Accreting Material
• Discovery of a very high energy gamma-ray signal from the 3C 66A/B region
• LABOCA observations of nearby, active galaxies
• On the relationship between BL Lacertae objects and radio galaxies
• Absorption of Nuclear Gamma-rays on the Starlight Radiation in FR I Sources: the Case of Centaurus A
• The millimeter-wave continuum spectrum of Centaurus A and its nucleus
• A novel method for measuring the extragalactic background light: Fermi application to the lobes of Fornax A
• Gamma-Ray Emission from the Broad-Line Radio Galaxy 3C111
• Compton X-ray and Gamma-ray Emission from Extended Radio Galaxies
• A synchrotron self-Compton model for the VHE gamma-ray emission from Cen A

Cited by in corpus (119)

• GeV Observations of Star-forming Galaxies with \textit{Fermi} LAT
• The Extragalactic Background Light and the Gamma-ray Opacity of the Universe
• Blazars as Ultra-High-Energy Cosmic-Ray Sources: Implications for TeV Gamma-Ray Observations
• First X-ray-Based Statistical Tests for Clumpy-Torus Models: Eclipse Events from 230 Years of Monitoring of Seyfert AGN
• Fermi Large Area Telescope Observations of Misaligned AGN
• Contribution of the Gamma-ray Loud Radio Galaxies Core Emissions to the Cosmic MeV and GeV Gamma-Ray Background Radiation
• Ultra-High-Energy Cosmic Rays
• Event Horizon Telescope observations of the jet launching and collimation in Centaurus A
• Compton Dominance and the Blazar Sequence
• Diffuse $\gamma$-ray emission from misaligned active galactic nuclei
• A Statistical Approach to Recognizing Source Classes for Unassociated Sources in the First Fermi-LAT Catalog
• High-Energy Neutrinos from Magnetized Coronae of Active Galactic Nuclei and Prospects for Identification of Seyfert Galaxies and Quasars in Neutrino Telescopes
• Fermi Large Area Telescope Observation of a Gamma-ray Source at the Position of Eta Carinae
• Particle acceleration in astrophysical jets
• TANAMI monitoring of Centaurus A: The complex dynamics in the inner parsec of an extragalactic jet
• Broad Line Radio Galaxies Observed with Fermi-LAT: The Origin of the GeV Gamma-Ray Emission
• Locating the gamma-ray emission region of the flat spectrum radio quasar PKS 1510-089
• The Extragalactic Gamma-ray Sky in the Fermi era
• The role of fast magnetic reconnection on the radio and gamma-ray emission from the nuclear regions of microquasars and low luminosity AGNs
• High energy gamma-ray properties of the FR I radio galaxy NGC 1275
• Active Galactic Nuclei under the scrutiny of CTA
• A strong radio brightening at the jet base of M87 during the elevated very-high-energy gamma-ray state in 2012
• Fornax A, Centaurus A and other radio galaxies as sources of ultra-high energy cosmic rays
• The Hard X-ray Emission of Cen A
• Evidence for a second component in the high-energy core emission from Centaurus A?
• The $\gamma$-ray spectrum of the core of Centaurus A as observed with H.E.S.S. and Fermi-LAT
• Probing Dark Matter with AGN Jets
• NuSTAR and XMM-Newton Observations of the Hard X-Ray Spectrum of Centaurus A
• Radio Galaxies at VHE energies
• Dual-frequency VLBI study of Centaurus A on sub-parsec scales
• The blazar-like radio structure of the TeV source IC310
• Deep Observation of the Giant Radio Lobes of Centaurus A with the Fermi Large Area Telescope
• Hadronic-Origin TeV gamma-Rays and Ultra-High Energy Cosmic Rays from Centaurus A
• Twelve and a Half Years of Observations of Centaurus A with RXTE
• Fermi-LAT Observation of Non-Blazar AGNs
• Non-thermal Processes in Black-Hole-Jet Magnetospheres
• One-zone SSC model for the core emission of Centaurus A revisited
• Rapid Gamma-ray variability of NGC 1275
• Non-thermal radiation from collisions of compact objects with intermediate scale jets in active galaxies
• Hadronic-Origin orphan TeV flare from the 1ES 1959+650
• VHE Gamma-Ray Induced Pair Cascades in the Radiation Fields of Dust Tori of AGN: Application to Cen A
• Suzaku Observations of gamma-Ray Bright Radio Galaxies: Origin of the X-ray Emission and Broad-Band Modelin
• First Multi-wavelength Campaign on the Gamma-ray-loud Active Galaxy IC 310
• Suzaku view of X-ray Spectral Variability of the Radio Galaxy Centaurus A : Partial Covering Absorber, Reflector, and Possible Jet Component
• Multiwavelength Astronomy and CTA: X-rays
• Discovery of a new extragalactic source population of energetic particles
• Modeling the Spectral Energy Distribution of the radio galaxy IC310
• Comparing 3C 120 jet emission at small and large scales
• Gamma-ray fluxes from the core emission of Centaurus A: A puzzle solved
• Neutrino, $\gamma$-ray and cosmic ray fluxes from the core of the closest radio galaxies
• General-relativistic model of hot accretion flows with global Compton cooling
• Implications for the structure of the relativistic jet from multiwavelength observations of NGC 6251
• Discovery of gamma-ray emission from the Broad Line Radio Galaxy Pictor A
• Hadronic origin of multi-TeV gamma rays and neutrinos from low-luminosity active galactic nuclei: implications of past activities of the Galactic center
• Multi-TeV flaring from blazars: Markarian 421 a case study
• Limits on X-ray Polarization at the Core of Centaurus A as Observed with the Imaging X-ray Polarimetry Explorer
• Some possible sources of IceCube TeV-PeV neutrino events
• Blazar Variability: A Study of Non-stationarity and the Flux-RMS Relation
• Suzaku X-ray Imaging of the Extended Lobe in the Giant Radio Galaxy NGC6251 Associated with the Fermi-LAT Source 2FGLJ1629.4+8236
• Fermi-LAT and Suzaku Observations of the Radio Galaxy Centaurus B
• Correlation of $\gamma$-ray and high-energy cosmic ray fluxes from the giant lobes of Centaurus A
• High energy emission component, population, and contribution to the extragalactic gamma-ray background of gamma-ray emitting radio galaxies
• Radio and Gamma-ray Properties of Extragalactic Jets from the TANAMI Sample
• The hard X-ray continuum of Cen A observed with INTEGRAL SPI
• Gamma-ray emission from proton-proton interactions in hot accretion flows
• 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
• Inverse Compton scattering of starlight in the kiloparsec-scale jet in Centaurus A: The origin of excess TeV $\gamma$-ray emission
• Search for high energy γ-ray emission from galaxies of the Local Group with Fermi/LAT
• Constraints on the gamma-ray emission from the cluster-scale AGN outburst in the Hydra A galaxy cluster
• TeV $\gamma$-ray fluxes from the long campaigns on Mrk421 as constraints on the emission of TeV-PeV Neutrinos and UHECRs
• Study of the PeV Neutrino, $\gamma$-rays and UHECRs around The Lobes of Centaurus A
• Comparisons of Jet Properties between GeV Radio Galaxies and Blazars
• Testing the linear relationship between black hole mass and variability timescale in low-luminosity AGN at submillimeter wavelengths
• Developing a method for soft gamma-ray Laue lens assembly and calibration
• TANAMI - Multiwavelength and Multimessenger Observations of Active Galaxies
• The multi-phase environment in the centre of Centaurus A
• Constraining Sources of Ultra High Energy Cosmic Rays Using High Energy Observations with the Fermi Satellite
• Radio Galaxies with the Cherenkov Telescope Array
• Signatures of leptophilic t-channel dark matter from active galactic nuclei
• High-Energy Gamma Rays and Neutrinos from Nearby Radio Galaxies
• The nature of the multi-wavelength emission of 3C 111
• Gamma-Rays from Non-Blazar AGN
• The 1.4 mm core of Centaurus A: First VLBI results with the South Pole Telescope
• Collisions of Jets of Particles from Active Galactic Nuclei with Neutralino Dark Matter
• Fermi-LAT Observations of Extreme Spectral Variability in IC 310
• Discovery of gamma-ray emission from a strongly lobe-dominated quasar 3C 275.1
• GeV-TeV gamma-rays produced by electrons in the kpc scale jet as a result of comptonization of the inner jet emission
• Very high-energy gamma-ray signature of ultrahigh-energy cosmic-ray acceleration in Centaurus A
• Limits on the source properties of FR-I galaxies from high-energy neutrino and gamma observations
• Broadband Modeling of Low Luminosity Active Galactic Nuclei Detected in Gamma Rays
• EBL effect on the observation of multi-TeV flaring of 2009 from Markarian 501
• The origin of multi-TeV flares from the nearest blazar Markarian 421
• Earth Occultation Imaging of the Low Energy Gamma-Ray Sky with GBM
• Hadronic modeling of TeV AGN: gammas and neutrinos
• Soft gamma-ray polarimetry with COSI using maximum likelihood analysis
• The WIMP-induced Gamma Ray Spectrum of Active Galactic Nuclei
• Testing Hadronic Models of Gamma Ray Production at the Core of Cen A
• Interpreting correlated observations of cosmic rays and gamma-rays from Centaurus A with a proton blazar inspired model
• Energetic Particles in Halos of Star Forming Galaxies
• A gamma-ray signature of energetic sources of cosmic-ray nuclei
• Analysis of Fermi-LAT observations, UHECRs and neutrinos from the radio galaxy Centaurus B
• Two active states of the narrow-line gamma-ray-loud AGN GB 1310+487
• The beaming effect for Fermi-LAT-detected FR-I radio galaxies
• A Soft X-Ray Lag Detected in Centaurus A
• Enhanced Gamma Ray Signals in Cosmic Proton-Wimp Collisions Due to Hadronization
• Constraints on Physical Conditions for the Acceleration on Ultra-high-energy Cosmic Rays in Nearby Active Galactic Nuclei Observed with the Fermi Large Area Telescope
• Morphology of TeV gamma-ray emission from the kpc scale jets in radio galaxies
• Blazar jet physics in the age of Fermi
• Neutrino production from photo-hadronic interactions of the gamma flux from Active Galactic Nuclei with their gas content
• Photo-Disintegration of Heavy Nuclei at the Core of Cen A
• An Analysis of Soft X-ray Structures at Kiloparsec Distances from the Active Nucleus of Centaurus A Galaxy
• Energetic Particles in the Central Starburst, Disc, and Halo of NGC253
• Cosmic connections: from cosmic rays to gamma rays, to cosmic backgrounds and magnetic fields
• High Energy Neutrinos and Cosmic Rays
• High-resolution monitoring of parsec-scale jets in the Fermi era
• Recent advances on multimessenger astrophysics: Centaurus A, GW 170817, and KM3-230213A
• The H.E.S.S. Extragalactic Sky
• Distributed accelerators in the jet of Centaurus A: the origin of the spectral hardening of very high energy gamma-rays