Search for anomalous features in gamma-ray blazar spectra corrected for the absorption on the extragalactic background light
arXiv:1810.03443 · doi:10.1088/1475-7516/2019/12/002
Abstract
We consider the ensemble of very-high-energy gamma-ray sources observed at distances and energies where a significant absorption of gamma rays is expected due to pair production on the extragalactic background light (EBL). Previous studies indicated that spectra of these sources, upon correction for the absorption, exhibit unusual spectral hardenings which happen precisely at the energies where the correction becomes significant. Here, we address this subject with the most recent clean sample of distant gamma-ray blazars, making use of published results of imaging atmospheric Cerenkov telescopes and of the Fermi-LAT Pass 8 data, supplemented by the newest absorption models and individual measurements of sources' redshifts. We perform a search for spectral breaks at energies corresponding to unit optical depth with respect to the absorption on EBL. These energies are different for distant and nearby objects, and consequently, such features may not be related to intrinsic properties of the sources. While in some spectra such breaks are not seen, hardenings at distance-dependent energies are present in many of them, though the overall statistical significance of the effect is lower than reported in previous studies. The dependence of the break strength on the redshift found earlier is not confirmed in the new analysis.
arXiv commentV2: 40 pages, 16 figures (43 panels). Considerable changes in the blazar sample resulted in reduced significance; discussions extended - version accepted by JCAP
References in corpus (81)
- The Seventh Data Release of the Sloan Digital Sky Survey
- The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
- The 2dF Galaxy Redshift Survey: Spectra and redshifts
- The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey
- A Unifying View of the Spectral Energy Distributions of Blazars
- The 6dF Galaxy Survey: Final Redshift Release (DR3) and Southern Large-Scale Structures
- Semi-analytic modeling of the EBL and consequences for extragalactic gamma-ray spectra
- Very-High-Energy Gamma Rays from a Distant Quasar: How Transparent Is the Universe?
- MAGIC discovery of VHE Emission from the FSRQ PKS 1222+21
- Deep Galaxy Counts, Extragalactic Background Light, and the Stellar Baryon Budget
- 3FHL: The Third Catalog of Hard Fermi-LAT Sources
- Intergalactic Photon Spectra from the Far IR to the UV Lyman Limit for and the Optical Depth of the Universe to High Energy Gamma-Rays
- The Sloan Digital Sky Survey Quasar Catalog III. Third Data Release
- Evidence for a new light spin-zero boson from cosmological gamma-ray propagation?
- Improved redshifts for SDSS quasar spectra
- The Imprint of The Extragalactic Background Light in the Gamma-Ray Spectra of Blazars
- Spectroscopy of The Largest Ever Gamma-ray Selected BL Lac Sample
- Spectroscopy of Broad Line Blazars from 1LAC
- The extragalactic background light, the Hubble constant, and anomalies: conclusions from 20 years of TeV gamma-ray observations
- An infrared background--TeV gamma-ray crisis?
- Measurement of the extragalactic background light imprint on the spectra of the brightest blazars observed with H.E.S.S
- From the Blazar Sequence to the Blazar Envelope: Revisiting the Relativistic Jet Dichotomy in Radio-loud AGN
- The Milky Way as a Kiloparsec-Scale Axionscope
- The extragalactic background light revisited and the cosmic photon-photon opacity
- A new interpretation of the gamma-ray observations of active galactic nuclei
- A -ray determination of the Universe's star-formation history
- Indications for a pair-production anomaly from the propagation of VHE gamma-rays
- Secondary photons and neutrinos from cosmic rays produced by distant blazars
- Fermi/LAT broad emission line blazars
- Formation of hard VHE gamma-ray spectra of blazars due to internal photon-photon absorption
- Extra-galactic background light measurements from the far-UV to the far-IR from deep ground and space-based galaxy counts
- Variations of the TeV energy spectrum at different flux levels of Mkn 421 observed with the HEGRA system of Cherenkov telescopes
- VHE gamma-ray emission of PKS 2155-304: spectral and temporal variability
- Optically Selected BL Lacertae Candidates from the Sloan Digital Sky Survey Data Release Seven
- The Properties of the X-Ray-Selected EMSS Sample of BL Lac Objects
- Very-high-energy gamma-rays from the Universe's middle age: detection of the z=0.940 blazar PKS 1441+25 with MAGIC
- Discovery of Very High Energy gamma-rays from 1ES 1011+496 at z=0.212
- New Spectral Evidence of an Unaccounted Component of the Near-infrared Extragalactic Background Light from the CIBER
- Unfolding of differential energy spectra in the MAGIC experiment
- VERITAS Discovery of >200GeV Gamma-ray Emission from the Intermediate-frequency-peaked BL Lac Object W Comae
- Radio-loud Active Galaxies in the Northern ROSAT All-Sky Survey III: New Spectroscopic Identifications from the RGB BL Lac Survey
- Radio galaxies of the local universe: all-sky catalog, luminosity functions, and clustering
- On the redshift of TeV BL Lac objects
- Super-GZK Photons from Photon-Axion Mixing
- Photon-axion mixing and ultra-high-energy cosmic rays from BL Lac type objects -- Shining light through the Universe
- Detection of very high energy gamma-ray emission from the gravitationally-lensed blazar QSO B0218+357 with the MAGIC telescopes
- A Three-Year Multi-Wavelength Study of the Very High Energy Gamma-ray Blazar 1ES 0229+200
- Axion-Like Particles and Recent Observations of the Cosmic Infrared Background Radiation
- An Empirical Determination of the Intergalactic Background Light from UV to FIR Wavelengths Using FIR Deep Galaxy Surveys and the Gamma-ray Opacity of the Universe
- Discovery of very high energy gamma rays from PKS 1424+240 and multiwavelength constraints on its redshift
- The Resolved Near-Infrared Extragalactic Background
- The Resolved NIR Extragalactic Background
- Discovery of VHE gamma-rays from the blazar 1ES 1215+303 with the MAGIC Telescopes and simultaneous multi-wavelength observations
- Discovery of VHE gamma-rays from the high-frequency-peaked BL Lac object RGB J0152+017
- Spectral analysis of Fermi-LAT blazars above 50 GeV
- MAGIC observations of the February 2014 flare of 1ES 1011+496 and ensuing constraint of the EBL density
- Discovery of hard-spectrum γ-ray emission from the BL Lac object 1ES 0414+009
- Extragalactic background Light: a measurement at 400 nm using dark cloud shadow II. Spectroscopic separation of dark cloud's light, and results
- Constraints on violation of Lorentz invariance from atmospheric showers initiated by multi-TeV photons
- Low-Resolution Spectrum of the Extragalactic Background Light with AKARI InfraRed Camera
- Optical spectroscopy of BL Lacertae objects. Broad lines, companion galaxies and redshift lower limits
- PKS 2005-489 at VHE: Four Years of Monitoring with HESS and Simultaneous Multi-wavelength Observations
- The Chandra Multi-Wavelength Project: Optical Spectroscopy and the Broadband Spectral Energy Distributions of X-ray Selected AGN
- Multi-wavelength Observations of H 2356-309
- On weak redshift dependence of gamma-ray spectra of distant blazars
- Detection of persistent VHE gamma-ray emission from PKS 1510-089 by the MAGIC telescopes during low states between 2012 and 2017
- Evidence for a cosmological effect in γ-ray spectra of BL Lacs
- H-alpha monitoring of OJ 287 in 2005-08
- Derivation of a large isotropic diffuse sky emission component at 1.25 and 2.2um from the COBE/DIRBE data
- H.E.S.S and Fermi-LAT discovery of gamma rays from the blazar 1ES 1312-423
- Prospective constraints on Lorentz violation from ultrahigh-energy photon detection
- Discovery of VHE gamma-rays from the BL Lac object PKS 0548-322
- Measurements of Diffuse Sky Emission Components in High Galactic Latitudes at 3.5 and 4.9 um Using DIRBE and WISE Data
- MAGIC detection of short-term variability of the high-peaked BL Lac object 1ES 0806+524
- Electromagnetic cascade masquerade: a way to mimic --axion-like particle mixing effects in blazar spectra
- Lorentz Invariance Violation Effects on Gamma-Gamma Absorption and Compton Scattering
- Axion-like particles and the propagation of gamma rays over astronomical distances
- Towards discrimination between galactic and intergalactic axion-photon mixing
- Derivation of a Relation for the Steepening of TeV Selected Blazar Gamma-ray Spectra with Energy and Redshift
- Constraining the star formation rate with the extragalactic background light
- An HST/COS Observation of Broad Ly Emission and Associated Absorption Lines of the BL Lacertae Object H 2356-309