Extragalactic background light inhomogeneities and Lorentz-Invariance Violation in gamma-gamma absorption and Compton scattering

2019 ◽  
Vol 15 (S356) ◽  
pp. 364-364
Author(s):  
Hassan Abdalla
Keyword(s):  
Compton Scattering ◽  
Gamma Ray ◽  
Lorentz Invariance ◽  
Energy Scale ◽  
Fundamental Physics ◽  
Extragalactic Background Light ◽  
Invariance Violation ◽  
Gamma Absorption ◽  
The Impact ◽  
Planck Energy

AbstractAt energies approaching the Planck energy scale 1019GeV, several quantum-gravity theories predict that familiar concepts such as Lorentz (LIV) symmetry can be broken. Such extreme energies are currently unreachable by experiments on Earth, but for photons traveling over cosmological distances the accumulated deviations from the Lorentz symmetry may be measurable using the Cherenkov Telescope Array (CTA). To study the spectral hardening feature observed in some VHE gamma-ray blazars, we calculate the reduction of the EBL gamma-gamma opacity due to the existence of underdense regions along the line of sight to VHE -gamma ray sources and we compared with the possibility of a LIV signature. Considering the LIV effect, we found that the cosmic opacity for VHE-gamma rays with energy more than 10 TeV can be strongly reduced. I will further discuss the impact of LIV on the Compton scattering process, and how future CTA observations may open an exciting window on studies of the fundamental physics.

scholarly journals Two-sided constraints on Lorentz invariance violation from Tibet-AS$$\gamma $$ and LHAASO very-high-energy photon observations

2021 ◽  
Vol 81 (8) ◽  
Author(s):  
Petr Satunin
Keyword(s):  
Gamma Ray ◽  
Lorentz Invariance ◽  
High Energy ◽  
Energy Scale ◽  
Production Constraints ◽  
Invariance Violation ◽  
Lorentz Invariance Violation ◽  
Very High Energy ◽  
Very High ◽  
Better Than

AbstractWe present new two-sided constraints on the Lorentz Invariance violation energy scale for photons with quartic dispersion relation from recent gamma ray observations by the Tibet-AS$$\gamma $$ γ and LHAASO experiments. The constraints are based on the consideration of the processes of photon triple splitting (superluminal scenario) and the suppression of shower formation (subluminal). The constraints in the subluminal scenario are better than the pair production constraints and are the strongest in the literature.

scholarly journals The Impact of Plasma Instabilities on the Spectra of TeV Blazars

2019 ◽  
Author(s):  
Rafael Alves Batista ◽  
Andrey Saveliev ◽  
Elisabete M de Gouveia Dal Pino
Keyword(s):  
Compton Scattering ◽  
Gamma Ray ◽  
High Energy ◽  
Plasma Instabilities ◽  
Cascade Process ◽  
Extragalactic Background Light ◽  
Inverse Compton Scattering ◽  
Inverse Compton ◽  
Very High Energy ◽  
The Impact

Abstract Relativistic jets from blazars are known to be sources of very-high-energy gamma rays (VHEGRs). During their propagation in the intergalactic space, VHEGRs interact with pervasive cosmological photon fields such as the extragalactic background light (EBL) and the cosmic microwave background (CMB), producing electron-positron pairs. These pairs can upscatter CMB/EBL photons to high energies via inverse Compton scattering, thereby continuing the cascade process. This is often used to set limits on intergalactic magnetic fields (IGMFs). However, the picture may change if plasma instabilities, arising due to the interaction of the pairs with the intergalactic medium (IGM), cool down the electrons/positrons faster than inverse Compton scattering. As a consequence, the kinetic energy lost by the pairs to the IGM could cause a hardening in the observed gamma-ray spectrum at energies below ∼100 GeV. Here we study several types and models of instabilities and assess their impact for interpreting observations of distant blazars. Our results suggest that plasma instabilities can describe the spectra of some blazars and mimic the effects of IGMFs, depending on parameters such as intrinsic spectrum of the object, the density and temperature of the IGM, and the luminosity of the beam. On the other hand, we find that for our fiducial set of parameters plasma instabilities do not have a major impact on the spectra of some of the blazars studied. Therefore, they may be used for constraining IGMFs.

scholarly journals Constraints on Lorentz Invariance Violation with Multiwavelength Polarized Astrophysical Sources

Galaxies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 44
Author(s):  
Qi-Qi Zhou ◽  
Shuang-Xi Yi ◽  
Jun-Jie Wei ◽  
Xue-Feng Wu
Keyword(s):  
Gamma Ray ◽  
Lorentz Invariance ◽  
Polarized Light ◽  
Polarization Plane ◽  
Polarization Angle ◽  
Intrinsic Polarization ◽  
Frequency Dependent ◽  
Invariance Violation ◽  
Linearly Polarized ◽  
Order Of Magnitude

Possible violations of Lorentz invariance (LIV) can produce vacuum birefringence, which results in a frequency-dependent rotation of the polarization plane of linearly polarized light from distant sources. In this paper, we try to search for a frequency-dependent change of the linear polarization angle arising from vacuum birefringence in the spectropolarimetric data of astrophysical sources. We collect five blazars with multiwavelength polarization measurements in different optical bands (UBVRI). Taking into account the observed polarization angle contributions from both the intrinsic polarization angle and the rotation angle induced by LIV, and assuming that the intrinsic polarization angle is an unknown constant, we obtain new constraints on LIV by directly fitting the multiwavelength polarimetric data of the five blazars. Here, we show that the birefringence parameter η quantifying the broken degree of Lorentz invariance is limited to be in the range of −9.63×10−8<η<6.55×10−6 at the 2σ confidence level, which is as good as or represents one order of magnitude improvement over the results previously obtained from ultraviolet/optical polarization observations. Much stronger limits can be obtained by future multiwavelength observations in the gamma-ray energy band.

scholarly journals Improved limits on Lorentz invariance violation from astrophysical gamma-ray sources

2019 ◽  
Vol 99 (4) ◽  
Author(s):  
Rodrigo Guedes Lang ◽  
Humberto Martínez-Huerta ◽  
Vitor de Souza
Keyword(s):  
Gamma Ray ◽  
Lorentz Invariance ◽  
Invariance Violation ◽  
Lorentz Invariance Violation

scholarly journals Lorentz Violation Footprints in the Spectrum of High-Energy Cosmic Neutrinos—Deformation of the Spectrum of Superluminal Neutrinos from Electron-Positron Pair Production in Vacuum

Symmetry ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1419 ◽  
Author(s):  
José Manuel Carmona ◽  
José Luis Cortés ◽  
José Javier Relancio ◽  
Maykoll Anthonny Reyes
Keyword(s):  
Pair Production ◽  
Numerical Simulations ◽  
Lorentz Invariance ◽  
Lorentz Violation ◽  
High Energy ◽  
Energy Scale ◽  
Invariance Violation ◽  
Electron Positron ◽  
Lorentz Invariance Violation ◽  
Electron Positron Pair

The observation of cosmic neutrinos up to 2 PeV is used to put bounds on the energy scale of Lorentz invariance violation through the loss of energy due to the production of e + e - pairs in the propagation of superluminal neutrinos. A model to study this effect, which allows us to understand qualitatively the results of numerical simulations, is presented.

Gamma-Ray Bursters and Lorentzian Relativity

2001 ◽  
Vol 56 (12) ◽  
pp. 889-892 ◽  
Author(s):  
F. Winterberg
Keyword(s):  
Event Horizon ◽  
Euclidean Geometry ◽  
Gamma Ray ◽  
Lorentz Invariance ◽  
Rest Mass ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Dynamic Interpretation ◽  
Balance Of Forces ◽  
Planck Energy

Abstract In the dynamic interpretation of relatively by Lorentz and Poincare, Lorentz invariance results from real physical contractions of measuring rods and slower going clocks in absolute motion against an ether. As it was shown by Thirring, this different interpretation of special relativity can be extended to general relativity, replacing the non-Euclidean with a Euclidean geometry, but where rods are contracted and clocks slowed down. In this dynamic interpretation of the special, (and by implication of the general) theory of relativity, there is a balance of forces which might be destroyed near the Planck energy, reached in approaching the event horizon. In gravitational collapse, the event horizon appears first at the center of the collapsing body, thereafter moving radially outward. If the balance of forces holding together elementary particles is destroyed near the event horizon, all matter would be converted into zero rest mass particles which could explain the large energy release of gamma ray bursters.

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