Turbulent spectra of the brightest gamma-ray flares of blazars

Abstract

We investigate the spectral properties of the brightest gamma-ray flares of blazars detected by the Fermi Large Area Telescope. We search for the presence of spectral breaks and measure the spectral curvature on typical time scales of a few days. We identify significant spectral breaks in fewer than half of the analyzed flares, but their parameters do not show any discernible regularities, and in particular there is no indication for gamma-ray absorption at any fixed source-frame photon energy. More interestingly, we find that the studied blazars are characterized by significant spectral variability. Gamma-ray flares of short duration are often characterized by strong spectral curvature, with the spectral peak located above 100 MeV. Since these spectral variations are observed despite excellent photon statistics, they must reflect temporal fluctuations in the energy distributions of the emitting particles. We suggest that highly regular gamma-ray spectra of blazars integrated over long time scales emerge from a superposition of many short-lived irregular components with relatively narrow spectra. This would imply that the emitting particles are accelerated in strongly turbulent environments.

arXiv comment11 pages, 3 figures, 2 tables, submitted to MNRAS

References in corpus (39)

• The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
• Fermi Large Area Telescope Second Source Catalog
• A Unifying View of the Spectral Energy Distributions of Blazars
• The Spectral Energy Distribution of Fermi bright blazars
• Relativistic Reconnection: an Efficient Source of Non-Thermal Particles
• The Second Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
• Limits and Confidence Intervals in the Presence of Nuisance Parameters
• Particle acceleration in relativistic collisionless shocks: Fermi process at last?
• The Fermi Large Area Telescope On Orbit: Event Classification, Instrument Response Functions, and Calibration
• Turbulent, Extreme Multi-Zone Model for Simulating Flux and Polarization Variability in Blazars
• Fast TeV variability in blazars: jets in a jet
• Formation of Hard Power-laws in the Energetic Particle Spectra Resulting from Relativistic Magnetic Reconnection
• Stability of Relativistic Jets from Rotating, Accreting Black Holes via Fully Three-Dimensional Magnetohydrodynamic Simulations
• MAGIC discovery of VHE Emission from the FSRQ PKS 1222+21
• Instability of toroidal magnetic field in jets and plerions
• Constraining Emission Models of Luminous Blazar Sources
• Gamma-ray Light Curves and Variability of Bright Fermi-Detected Blazars
• The extent of power-law energy spectra in collisionless relativistic magnetic reconnection in pair plasmas
• Log-parabolic spectra and particle acceleration in blazars. III: SSC emission in the TeV band from Mkn 501
• GeV breaks in blazars as a result of gamma-ray absorption within the broad-line region
• Spectral Properties of Bright Fermi-detected Blazars in the Gamma-ray Band
• Fermi Gamma-ray Space Telescope Observations of the Gamma-ray Outburst from 3C 454.3 in November 2010
• Early Fermi Gamma-ray Space Telescope Observations of the Quasar 3C 454.3
• Fermi Gamma-ray Space Telescope Observations of Recent Gamma-ray Outbursts from 3C 454.3
• The spectrum of the Broad Line Region and the high-energy emission of powerful blazars
• Very Rapid High-Amplitude Gamma-ray Variability in Luminous Blazar PKS 1510-089 Studied with Fermi-LAT
• Causality and stability of cosmic jets
• H.E.S.S. discovery of VHE gamma-rays from the quasar PKS 1510-089
• Constraining the Location of Gamma-Ray Flares in Luminous Blazars
• On the Spectral Break in the Fermi-LAT Spectrum of 3C 454.3
• MAGIC gamma-ray and multifrequency observations of flat spectrum radio quasar PKS 1510-089 in early 2012
• Fermi Large Area Telescope Detection of Bright Gamma-ray Outbursts from a Peculiar Quasar 4C +21.35
• The brightest gamma-ray flares of blazars
• Gamma-ray blazars near equipartition and the origin of the GeV spectral break in 3C 454.3
• Variation of the gamma-gamma opacity by the He II Lyman continuum constrains the location of the gamma-ray emission region in the blazar 3C 454.3
• The mystery of spectral breaks: Lyman continuum absorption by photon-photon pair production in the Fermi GeV spectra of bright blazars
• Identifying Breaks and Curvature in the Fermi Spectra of Bright Flat Spectrum Radio Quasars
• An Investigation into the Spectral Properties of Bright Fermi Blazars
• Entropy Production in Relativistic Jet Boundary Layers

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• Fermi-LAT Observations of the 2014 May-July outburst from 3C 454.3
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• Property Studies of "Loner" Flares of Gamma-Ray Blazars
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