Collective Evidence for Inverse Compton Emission from External Photons in High-Power Blazars

Abstract

We present the first collective evidence that Fermi-detected jets of high kinetic power (L_kin) are dominated by inverse Compton emission from upscattered external photons. Using a sample with a broad range in orientation angle, including radio galaxies and blazars, we find that very high power sources (L_kin > 10^45.5 erg s^{-1}) show a significant increase in the ratio of inverse Compton to synchrotron power (Compton dominance) with decreasing orientation angle, as measured by the radio core dominance and confirmed by the distribution of superluminal speeds. This increase is consistent with beaming expectations for external Compton (EC) emission, but not for synchrotron self Compton (SSC) emission. For the lowest power jets (L_kin < 10^43.5 erg s^{-1}), no trend between Compton and radio core dominance is found, consistent with SSC. Importantly, the EC trend is not seen for moderately high power flat spectrum radio quasars with strong external photon fields. Coupled with the evidence that jet power is linked to the jet speed (Kharb et al. 2010), this finding suggests that external photon fields become the dominant source of seed photons in the jet comoving frame only for the faster and therefore more powerful jets.

Accepted for Publication in ApJ Letters, 5 pages, 4 figures

References in corpus (8)

• The Second Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
• Sub-milliarcsecond Imaging of Quasars and Active Galactic Nuclei III. Kinematics of Parsec-Scale Radio Jets
• Modeling the Emission Processes in Blazars
• A simplified view of blazars: clearing the fog around long-standing selection effects
• From the Blazar Sequence to the Blazar Envelope: Revisiting the Relativistic Jet Dichotomy in Radio-loud AGN
• On the Location of the Gamma-ray Emission in the 2008 Outburst in the BL Lacertae Object AO 0235+164 through Observations across the Electromagnetic Spectrum
• Broad Line Radio Galaxies Observed with Fermi-LAT: The Origin of the GeV Gamma-Ray Emission
• The discovery of high power - high synchrotron peak blazars

Cited by in corpus (34)

• The Third Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
• The Cosmic Evolution of Fermi BL Lacertae Objects
• A hadronic origin for ultra-high-frequency-peaked BL Lac objects
• Compton Dominance and the Blazar Sequence
• The nature of the Diffuse Gamma-Ray Background
• Constraining the Location of Gamma-Ray Flares in Luminous Blazars
• Connecting radio variability to the characteristics of gamma-ray blazars
• 4.5 years multi-wavelength observations of Mrk 421 during the ARGO-YBJ and Fermi common operation time
• Fermi non-detections of four X-ray jet sources and implications for the IC/CMB mechanism
• An X-ray and Multiwavelength Survey of Highly Radio-Loud Quasars at z > 4: Jet-Linked Emission in the Brightest Radio Beacons of the Early Universe
• Discovery of a new TeV gamma-ray source: VER J0521+211
• A method for localizing energy dissipation in blazars using Fermi variability
• Synchrotron and inverse-Compton emission from blazar jets - III. Compton-dominant blazars
• Time-dependent simulations of emission from FSRQ PKS1510-089: multiwavelength variability of external Compton and SSC models
• Near-Equipartition Jets with Log-Parabola Electron Energy Distribution and the Blazar Spectral-Index Diagrams
• H.E.S.S. detection of very-high-energy gamma-ray emission from the quasar PKS 0736+017
• Fourier Analysis of Blazar Variability: Klein-Nishina Effects and the Jet Scattering Environment
• The Radio/Gamma Connection of Blazars from High to Low Radio Frequencies
• Luminous and high-frequency peaked blazars: the origin of the $\gamma$-ray emission from PKS 1424+240
• Curvature of the spectral energy distribution, the dominant process for inverse Compton component and other jet properties in Fermi 2LAC blazars
• VERITAS Discovery of VHE Emission from the Radio Galaxy 3C 264: A Multi-Wavelength Study
• Astrophysical interpretation of the anisotropies in the unresolved gamma-ray background
• Modeling the Spectral Energy Distributions and Spectropolarimetry of Blazars -- Application to 4C+01.02 in 2016-2017
• High Energy Polarization of Blazars : Detection Prospects
• Optical and Gamma-Ray Variability Behaviors of 3C 454.3 from 2006 to 2011
• What determines the observational differences of blazars?
• Powerful extragalactic jets dissipate their kinetic energy far from the central black hole
• Circumnuclear Dust in AP Librae and the source of its VHE emission
• A complete sample of LSP blazars fully described in $\gamma$-rays. New $\gamma$-ray detections and associations with Fermi-LAT
• Locating the GeV Emission Region in the Jets of Blazars from Months-Timescale Multi-Wavelength Outbursts
• Observations of very high energy gamma-ray emission from AGNs with the ground-based EAS arrays
• A numerical study on the role of instabilities on multi-wavelength emission signatures of blazar jets
• A Physical Model for the Revised Blazar Sequence
• The Gamma-ray Luminosity Function of Flat-Spectrum Radio Quasars