Revisiting the evidences for spectral anomalies in distant blazars: new data on the photon-ALP mixing

Abstract

We re-examine possible dependencies on redshift of the spectral parameters of blazars observed at very-high energies (VHEs) with Imaging Atmospheric Cherenkov telescopes (IACTs). This is relevant to assess potential effects with the source distance of the photon to axion-like particle (ALP) mixing, that would deeply affect the propagation of VHE photons across the Universe. We focus our spectral analysis on 38 BL Lac objects (32 high-peaked and 6 intermediate-peaked) up to redshift $z\simeq 0.5$, and a small sample of 5 Flat Spectrum Radio Quasars up to $z=1$ treated independently to increase the redshift baseline. The 78 independent spectra of these sources are first of all carefully corrected for the gamma-gamma interaction with photons of the Extragalactic Background Light, that are responsible for the major redshift-dependent opacity effect. Then, the corrected spectra are fitted with simple power-laws to infer the intrinsic spectral indices ${\Gamma }_{\mathrm{em}}$ at VHE, to test the assumption that such spectral properties are set by the local rather than the global cosmological environment. We find some systematic anti-correlations with redshift of ${\Gamma }_{\mathrm{em}}$ that might indicate, although with low-significance, a spectral anomaly potentially requiring a revision of the photon propagation process. More conclusive tests with higher statistical significance will require the observational improvements offered by the forthcoming new generation of Cherenkov arrays (CTA, ASTRI, LHAASO).

arXiv comment17 pages, 12 figures

References in corpus (106)

• Potential Sensitivity of Gamma-Ray Burster Observations to Wave Dispersion in Vacuo
• A Unifying View of the Spectral Energy Distributions of Blazars
• Magnetic Fields in the Early Universe
• The Low-Energy Frontier of Particle Physics
• New CAST Limit on the Axion-Photon Interaction
• The extragalactic optical-infrared background radiations, their time evolution and the cosmic photon-photon opacity
• WISPy Cold Dark Matter
• Cosmological Magnetic Fields: Their Generation, Evolution and Observation
• Extragalactic Background Light Inferred from AEGIS Galaxy SED-type Fractions
• Modeling the Extragalactic Background Light from Stars and Dust
• Semi-analytic modeling of the EBL and consequences for extragalactic gamma-ray spectra
• Revisiting the bound on axion-photon coupling from Globular Clusters
• Revisiting the SN1987A gamma-ray limit on ultralight axion-like particles
• MAGIC discovery of VHE Emission from the FSRQ PKS 1222+21
• Deep Galaxy Counts, Extragalactic Background Light, and the Stellar Baryon Budget
• Evidence for a new light spin-zero boson from cosmological gamma-ray propagation?
• Search for Spectral Irregularities due to Photon-Axionlike-Particle Oscillations With the Fermi Large Area Telescope
• Science with the Cherenkov Telescope Array
• The blazar TXS 0506+056 associated with a high-energy neutrino: insights into extragalactic jets and cosmic ray acceleration
• Invariance Violation Extends the Cosmic Ray Horizon ?
• New Tests of Lorentz Invariance Following from Observations of the Highest Energy Cosmic Gamma Rays
• The Milky Way as a Kiloparsec-Scale Axionscope
• The extragalactic background light revisited and the cosmic photon-photon opacity
• Hints of the existence of Axion-Like-Particles from the gamma-ray spectra of cosmological sources
• New limits on extragalactic magnetic fields from rotation measures
• Observations of Mkn 421 with the MAGIC Telescope
• Astrophysical limits on very light axion-like particles from Chandra grating spectroscopy of NGC 1275
• Detection of VHE gamma-ray emission from the distant blazar 1ES 1101-232 with H.E.S.S. and broadband characterisation
• Implications of Cosmological Gamma-Ray Absorption - I.Evolution of the Metagalactic Radiation Field
• VHE gamma-ray emission of PKS 2155-304: spectral and temporal variability
• Discovery of very high energy gamma-ray emission from the low-frequency peaked BL Lacertae object BL Lacertae
• Very-high-energy gamma-rays from the Universe's middle age: detection of the z=0.940 blazar PKS 1441+25 with MAGIC
• Constraints on the Extragalactic Infrared Background from Gamma Ray Observations of Mrk 501
• Discovery of Very High Energy gamma-rays from 1ES 1011+496 at z=0.212
• New constraints on light Axion-Like Particles using Chandra Transmission Grating Spectroscopy of the powerful cluster-hosted quasar H1821+643
• Rapid TeV Gamma-Ray Flaring of BL Lacertae
• Discovery of VHE gamma-ray emission from 1ES1218+30.4
• Spectral Energy Distribution of Markarian 501: Quiescent State vs. Extreme Outburst
• Discovery of Very High Energy $\gamma$-Rays from Markarian~180 Triggered by an Optical Outburst
• Simultaneous multiwavelength observations of the blazar 1ES1959+650 at a low TeV flux
• Gamma rays from the quasar PKS 1441+25: story of an escape
• VERITAS Discovery of >200GeV Gamma-ray Emission from the Intermediate-frequency-peaked BL Lac Object W Comae
• The Blazar PG 1553+113 as a Binary System of Supermassive Black Holes
• VERITAS Observations of a Very High Energy Gamma-ray Flare from the Blazar 3C 66A
• Discovery of Very High Energy gamma-rays from the blazar S5 0716+714
• Multiwavelength observations of a TeV-Flare from W Comae
• Detection of very high energy gamma-ray emission from the gravitationally-lensed blazar QSO B0218+357 with the MAGIC telescopes
• The Discovery of gamma-Ray Emission From The Blazar RGB J0710+591
• Detection of VHE radiation from the BL Lac PG 1553+113 with the MAGIC telescope
• Photon propagation and the VHE gamma-ray spectra of blazars: how transparent is really the Universe?
• 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
• Constraints on Axion-Like Particles from X-ray Observations of NGC1275
• Sensitivity of the Cherenkov Telescope Array for probing cosmology and fundamental physics with gamma-ray propagation
• Observation of very high energy gamma-rays from the AGN 1ES 2344+514 in a low emission state with the MAGIC telescope
• Search for Axionlike-Particle-Induced Prompt Gamma-Ray Emission from Extragalactic Core-Collapse Supernovae with the Fermi Large Area Telescope
• Observation of VHE gamma-ray emission from the Active Galactic Nucleus 1ES1959+650 using the MAGIC telecope
• Discovery of VHE Gamma Rays from PKS 2005-489
• Constraints on Axion-Like Particles from Non-Observation of Spectral Modulations for X-ray Point Sources
• Discovery of VHE gamma-rays from the blazar 1ES 1215+303 with the MAGIC Telescopes and simultaneous multi-wavelength observations
• Discovery of Very High Energy Gamma-Ray Emission from the BL Lac Object H2356-309 with the H.E.S.S. Cherenkov Telescopes
• Inspecting absorption in the spectra of extra-galactic gamma-ray sources for insight into Lorentz invariance violation
• Axion-like particle effects on the polarization of cosmic high-energy gamma sources
• Blazar VHE spectral alterations induced by photon-ALP oscillations
• Discovery of Very High-Energy Gamma-Ray Radiation from the BL Lac 1ES 0806+524
• Behavior of axion-like particles in smoothed out domain-like magnetic fields
• Discovery of hard-spectrum γ-ray emission from the BL Lac object 1ES 0414+009
• Multi-wavelength characterization of the blazar S5~0716+714 during an unprecedented outburst phase
• Extragalactic photon--axion-like particle oscillations up to 1000 TeV
• On the detectability of Lorentz invariance violation through anomalous multi-TeV $\gamma$-ray spectra of blazars
• PKS 2005-489 at VHE: Four Years of Monitoring with HESS and Simultaneous Multi-wavelength Observations
• Discovery of High-energy and Very High Energy Gamma-ray Emission from the Blazar RBS 0413
• Detection of persistent VHE gamma-ray emission from PKS 1510-089 by the MAGIC telescopes during low states between 2012 and 2017
• VERITAS observations of the BL Lac object TXS 0506+056
• Hint at an axion-like particle from the redshift dependence of blazar spectra
• The CTA Sensitivity to Lorentz-Violating Effects on the Gamma-Ray Horizon
• Multiwavelength Observations of the VHE Blazar 1ES 2344+514
• Multiwavelength Observations of the Previously Unidentified Blazar RX J0648.7+1516
• Discovery of TeV gamma-ray emission from PKS 0447-439 and derivation of an upper limit on its redshift
• H.E.S.S and Fermi-LAT discovery of gamma rays from the blazar 1ES 1312-423
• Multiwavelength observations of the AGN 1ES 0414+009 with VERITAS, Fermi-LAT, Swift-XRT, and MDM
• Discovery of VHE gamma-rays from the BL Lac object PKS 0548-322
• VERITAS detection of $\gamma$-ray flaring activity from the BL Lac object 1ES 1727+502 during bright moonlight observations
• Discovery of VHE gamma-ray emission from the BL Lac object B3 2247+381 with the MAGIC telescopes
• Discovery of VHE γ-ray emission and multi-wavelength observations of the BL Lac object 1RXS J101015.9-311909
• MAGIC detection of short-term variability of the high-peaked BL Lac object 1ES 0806+524
• Discovery of very high energy gamma-ray emission from the BL Lac object PKS 0301-243 with H.E.S.S
• Long term observations of B2 1215+30 with VERITAS
• VHE gamma-ray detection of FSRQ QSO B1420+326 and modeling of its enhanced broadband state in 2020
• VERITAS Observations of the BL Lac Object PG 1553+113
• Discovery of high and very high-energy emission from the BL Lac object SHBL J001355.9-185406
• On the distance of PG 1553+11. A lineless BL Lac object active in the TeV band
• Searching for Axion-Like Particles with X-ray Polarimeters
• Very high energy $\gamma$-ray emission from two blazars of unknown redshift and upper limits on their distance
• Insights into the emission of the blazar 1ES 1011+496 through unprecedented broadband observations during 2011 and 2012
• Fundamental physics with blazar spectra: a critical appraisal
• MAGIC detection of very high energy gamma-ray emission from the low-luminosity blazar 1ES 1741+196
• Very-High-Energy $\gamma$-Ray Observations of the Blazar 1ES 2344+514 with VERITAS
• Discovery of very high energy gamma-ray emission from the blazar 1ES 0033+595 by the MAGIC telescopes
• VERITAS and Multiwavelength Observations of the BL Lacertae Object 1ES 1741+196
• Updated Bounds on Axion-Like Particles from X-ray Observations
• Photon-ALP interaction as a measure of initial photon polarization
• Multi-Wavelength Observations of the Blazar 1ES 1011+496 in Spring 2008
• Discovery of Very High Energy Gamma Rays from 1ES 1440+122
• High zenith angle observations of PKS 2155-304 with the MAGIC-I telescope
• Very high-energy observations of the two high-frequency peaked BL Lac objects 1ES 1218+304 and H 1426+428

Cited by in corpus (1)

• Propagation of very-high-energy $\gamma$-rays from distant blazars