Blazar Gamma-Rays, Shock Acceleration, and the Extragalactic Background Light

Abstract

The observed spectra of blazars, their intrinsic emission, and the underlying populations of radiating particles are intimately related. The use of these sources as probes of the extragalactic infrared background, a prospect propelled by recent advances in TeV-band telescopes, soon to be augmented by observations by NASA's upcoming Gamma-Ray Large Area Space Telescope (GLAST), has been a topic of great recent interest. Here, it is demonstrated that if particles in blazar jets are accelerated at relativistic shocks, then gamma-ray spectra with indices less than 1.5 can be produced. This, in turn, loosens the upper limits on the near infrared extragalactic background radiation previously proposed. We also show evidence hinting that TeV blazars with flatter spectra have higher intrinsic TeV gamma-ray luminosities and we indicate that there may be a correlation of flatness and luminosity with redshift.

Version to appear in ApJ Letters, Vol. 667, 20 Sept. 2007

References in corpus (21)

• Infrared luminosity functions from the Chandra Deep Field South : the Spitzer view on the history of dusty star formation at 0<z<1
• A low level of extragalactic background light as revealed by gamma-rays from blazars
• Spitzer view on the evolution of star-forming galaxies from z=0 to z~3
• Intergalactic Photon Spectra from the Far IR to the UV Lyman Limit for $0<z<6$ and the Optical Depth of the Universe to High Energy Gamma-Rays
• Particle acceleration at ultrarelativistic shocks: an eigenfunction method
• The GALEX-VVDS Measurement of the Evolution of the Far-Ultraviolet Luminosity Density and the Cosmic Star Formation Rate
• Energy spectra of cosmic rays accelerated at ultrarelativistic shock waves
• Ultra-high-energy cosmic ray acceleration by relativistic blast waves
• Acceleration Rates and Injection Efficiencies in Oblique Shocks
• Modelling the TeV gamma-ray spectra of two low redshift AGNs: Mkn 501 and Mkn 421
• Non-linear Particle Acceleration in Oblique Shocks
• Hard TeV spectra of blazars and the constraints to the IR intergalactic background
• Diffusive Shock Acceleration in Unmodified Relativistic, Oblique Shocks
• Predicted Extragalactic TeV Gamma-Ray Sources
• Extragalactic Gamma-ray Absorption and the Intrinsic Spectrum of Mkn 501 During the 1997 Flare
• Observation of very high energy gamma-rays from the AGN 1ES 2344+514 in a low emission state with the MAGIC telescope
• Observation of VHE gamma-ray emission from the Active Galactic Nucleus 1ES1959+650 using the MAGIC telecope
• On possible `cosmic ray cocoons' of relativistic jets
• Corrected Table for the Parametric Coefficients for the Optical Depth of the Universe to Gamma-rays at Various Redshifts
• Diffusive Shock Acceleration of High Energy Cosmic Rays
• A Simple Analytic Treatment of the Intergalactic Absorption Effect in Blazar Gamma-ray Spectra

Cited by in corpus (90)

• Extragalactic Background Light Inferred from AEGIS Galaxy SED-type Fractions
• Modeling the Extragalactic Background Light from Stars and Dust
• Very-High-Energy Gamma Rays from a Distant Quasar: How Transparent Is the Universe?
• High-energy neutrinos in the context of multimessenger physics
• Teraelectronvolt Astronomy
• New constraints on the Mid-IR EBL from the HESS discovery of VHE gamma rays from 1ES 0229+200
• The Extragalactic Background Light and the Gamma-ray Opacity of the Universe
• TeV BL Lac objects at the dawn of the Fermi era
• The Diffuse Supernova Neutrino Background is detectable in Super-Kamiokande
• The Milky Way as a Kiloparsec-Scale Axionscope
• Hints of the existence of Axion-Like-Particles from the gamma-ray spectra of cosmological sources
• Determination of intergalactic magnetic fields from gamma ray data
• New synthesis models of consistent extragalactic background light over cosmic time
• Cosmic Neutrino Pevatrons: A Brand New Pathway to Astronomy, Astrophysics, and Particle Physics
• Role of line-of-sight cosmic ray interactions in forming the spectra of distant blazars in TeV gamma rays and high-energy neutrinos
• Diffusive Acceleration of Particles at Oblique, Relativistic, Magnetohydrodynamic Shocks
• Secondary photons and neutrinos from cosmic rays produced by distant blazars
• TeV and Multi-wavelength Observations of Mrk 421 in 2006-2008
• Formation of hard VHE gamma-ray spectra of blazars due to internal photon-photon absorption
• Hardening of TeV gamma spectrum of AGNs in galaxy clusters by conversions of photons into axion-like particles
• Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe
• Formation of hard very-high energy spectra of blazars in leptonic models
• Constraints on the Intergalactic Magnetic Field with Gamma-Ray Observations of Blazars
• Planck early results. XV. Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources
• PeV neutrinos from intergalactic interactions of cosmic rays emitted by active galactic nuclei
• The Hard VHE Gamma-ray Emission in High-Redshift TeV Blazars: Comptonization of Cosmic Microwave Background Radiation in an Extended Jet?
• Stochastic conversions of TeV photons into axion-like particles in extragalactic magnetic fields
• Probing Intergalactic Magnetic Fields in the GLAST Era through Pair Echo Emission from TeV Blazars
• Evidence for an axion-like particle from PKS 1222+216?
• The Discovery of gamma-Ray Emission From The Blazar RGB J0710+591
• Photon propagation and the VHE gamma-ray spectra of blazars: how transparent is really the Universe?
• The hard TeV spectrum of 1ES 0229+200: new clues from Swift
• Probing Acceleration and Turbulence at Relativistic Shocks in Blazar Jets
• Discovery of Variability in the Very High Energy Gamma-Ray Emission of 1ES 1218+304 with VERITAS
• Limits on the extragalactic background light in the Fermi era
• The Extragalactic Gamma-ray Sky in the Fermi era
• Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009
• The stellar contribution to the extra-galactic background light and absorption of high-energy gamma-rays
• 4.5 years multi-wavelength observations of Mrk 421 during the ARGO-YBJ and Fermi common operation time
• Synoptic studies of seventeen blazars detected in very high-energy gamma-rays
• Discovery of a very high energy gamma-ray signal from the 3C 66A/B region
• Monte Carlo Simulations of Nonlinear Particle Acceleration in Parallel Trans-relativistic Shocks
• Multiwavelength Variability Signatures of Relativistic Shocks in Blazar Jets
• Axion-like particle imprint in cosmological very-high-energy sources
• Leptonic/hadronic models for electromagnetic emission in microquasars: the case of GX 339-4
• Fermi Observations of the Very Hard Gamma-ray Blazar PG 1553+113
• Time-Dependent Searches for Point Sources of Neutrinos with the 40-String and 22-String Configurations of IceCube
• High-Energy Neutrinos from Active Galactic Nuclei
• On The Heavy Chemical Composition of the Ultra-High Energy Cosmic Rays
• On weak redshift dependence of gamma-ray spectra of distant blazars
• Constraints on the Extragalactic Background Light from Very High Energy Gamma-Ray Observations of Blazars
• Modification of the gamma-ray spectra by internal absorption in OVV blazars: The example cases of 3C 273 and 3C 279
• A method for setting upper limits to the extragalactic background light with Fermi-LAT and TeV observations of blazars
• Nonlinear particle acceleration and thermal particles in GRB afterglows
• Optical depth for VHE gamma-rays from distant sources from a generic EBL density
• First stars and the extragalactic background light: How recent gamma-ray observations constrain the early universe
• Bottom-up Acceleration of Ultra-High-Energy Cosmic Rays in the Jets of Active Galactic Nuclei
• The Spectrum of 1ES0229 + 200 and the Cosmic Infrared Background
• No Indications of Axion-Like Particles From Fermi
• High-frequency-peaked BL Lacertae objects as spectral candles to measure the Extragalactic Background Light in the Fermi and air Cherenkov telescopes era
• A New Model for Gamma-Ray Cascades in Extragalactic Magnetic Fields
• Constraints to Energy Spectra of Blazars based on Recent EBL Limits from Galaxy Counts
• Is the Universe More Transparent to Gamma Rays Than Previously Thought?
• Prediction of the diffuse neutrino flux from cosmic ray interactions near Supernova Remnants
• A novel method for measuring the extragalactic background light: Fermi application to the lobes of Fornax A
• Non-variable TeV emission from the extended jet of a blazar in the stochastic acceleration scenario: the case of the hard TeV emission of 1ES 1101-232
• Active Galactic Nuclei Jets and Multiple Oblique Shock Acceleration: Starved Spectra
• Absorption of 10 Gev--1 Tev Gamma Rays from 3C 279
• Studies of active galactic nuclei with CTA
• A Suzaku X-Ray Study of the Particle Acceleration Processes in the Relativistic Jet of Blazar Mrk 421
• A Two-Zone Model as origin of Hard TeV Spectrum in Extreme BL Lacs
• Hard Electron Energy Distribution in the Relativistic Shocks of GRB Afterglows
• Probing the Transition Between the Synchrotron and Inverse-compton Spectral Components of 1ES 1959+650
• Intergalactic absorption and blazar gamma-ray spectra
• Formation of very hard electron and gamma-ray spectra of flat spectrum radio quasar in fast-cooling regime
• Novel Techniques for Decomposing Diffuse Backgrounds
• A physical model for the origin of the diffuse cosmic infrared background
• Long-term X-ray emission from Swift J1644+57
• Using Gamma-Ray Burst Prompt Emission to Probe Relativistic Shock Acceleration
• An original constraint on the Hubble constant: h>0.74
• The spectrum of Cosmic Rays escaping from relativistic shocks
• High-Energy Neutrino Fluxes from Hard-TeV BL Lacs
• Propagation of very-high-energy $\gamma$-rays from distant blazars
• Constraints on the Optical-IR extragalactic background from gamma-ray absorption studies
• Multiwavelength Probes of the Environs of Relativistic Shocks in Blazar Jets
• Multiwavelength Observations of Markarian 421 in 2005 - 2006
• Dark Matter and Fundamental Physics Searches with IACTs
• Lepton Acceleration in Pulsar Wind Nebulae
• A new light boson from MAGIC observations?
• Physics Insights from Recent MAGIC AGN Observations