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Related papers: Propagation of very-high-energy $\gamma$-rays from…

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Interactions between the extragalactic background light (EBL) and very high energy {\gamma} rays (VHE; E > 10 GeV) from cosmological sources alter their {\gamma}-ray spectrum. The stronger absorption of harder {\gamma} rays causes a…

Astrophysics of Galaxies · Physics 2018-08-21 A. M. Kudoda , A. Faltenbacher

Very high energy (VHE) gamma-rays undergo pair production with low energy photons of background radiation fields. This leads to an attenuation of the primary gamma-ray flux of extragalactic sources in the interaction with the extragalactic…

High Energy Astrophysical Phenomena · Physics 2014-10-08 Manuel Meyer , Dieter Horns

The very high energy (VHE) gamma ray spectral index of high energy peaked blazars correlates strongly with its corresponding redshift whereas no such correlation is observed in the X-ray or the GeV bands. We attribute this correlation to a…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Atreyee Sinha , Sunder Sahayanathan , Ranjeev Misra , Sagar Godambe , B. S. Acharya

The direct measurement of the extragalactic background light (EBL) is difficult at optical to infrared wavelengths because of the strong foreground radiation originating in the Solar System. Very high energy (VHE, E$>$100 GeV) gamma rays…

Astrophysics · Physics 2009-09-29 M. Schroedter

Discoveries of very high energy (VHE) photons from distant blazars suggest that, after correction by extragalactic background light (EBL) absorption, there is a flatness or even a turn-up in their spectra at the highest energies that cannot…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 A. Dominguez , M. A. Sanchez-Conde , F. Prada

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…

High Energy Astrophysical Phenomena · Physics 2022-08-17 Francesco Cenedese , Alberto Franceschini , Giorgio Galanti

The intrinsic flux of very high energy (VHE, Energy > 100 GeV) gamma-rays from extragalactic sources is attenuated due to pair production in the interaction with photons of the extragalactic background light (EBL). Depending on the distance…

High Energy Astrophysical Phenomena · Physics 2014-10-08 Manuel Meyer , Dieter Horns , Martin Raue

The very high energy (VHE, E $>$ $100 \mathrm~{GeV}$) $\gamma$-ray observations offer a possibility of indirectly detecting the presence of axion-like particles (ALPs). The paper focuses on detecting photon-ALP oscillations on $\gamma$-ray…

High Energy Astrophysical Phenomena · Physics 2025-03-03 L. J. Dong , Y. G. Zheng , S. J. Kang , C. Y. Yang

The very high energy (VHE) gamma-ray spectral indices of blazars show strong correlation with the source redshift. Absence of any such correlation in low energy gamma rays and X-rays indicate the presence of Extragalactic Background Light…

High Energy Astrophysical Phenomena · Physics 2022-02-23 Malik Zahoor , Sunder Sahayanathan , Shah Zahir , Naseer Iqbal , Aaqib Manzoor , Nilay Bhatt

The unexpectedly hard very-high-energy (VHE; $E > 100$ GeV) $\gamma$-ray spectra of a few distant blazars have been interpreted as evidence for a reduction of the $\gamma\gamma$ opacity of the Universe due to the interaction of VHE…

High Energy Astrophysical Phenomena · Physics 2017-02-08 Hassan Abdalla , Markus Boettcher

The absorption of gamma-rays in the intergalactic medium due to the EBL (Extragalactic Background Light) causes the observed blazar spectrum to be fainter and softer than their intrinsic state. It could thus be expected to see an effective…

High Energy Astrophysical Phenomena · Physics 2009-01-22 B. Behera , S. J. Wagner

The extragalactic background light (EBL) from the infrared to the ultraviolet is difficult to measure directly, but can be constrained with a variety of methods. EBL photons absorb gamma-rays from distant blazars, allowing one to use blazar…

High Energy Astrophysical Phenomena · Physics 2014-11-18 Justin D. Finke , Soebur Razzaque

Many extensions of the Standard Model predict the existence of ALPs, which are very light spin-zero bosons with a two-photon coupling. Photon-ALP oscillations occur in the presence of an external magnetic field, and ALPs can lead to…

High Energy Astrophysical Phenomena · Physics 2015-03-19 Alessandro De Angelis , Giorgio Galanti , Marco Roncadelli

The extragalactic background light (EBL) in the IR to UV bands partly absorbs very high energy (VHE, $E \geq$ 100GeV) $\gamma-$ray photons travelling over cosmological distances via pair production. In this paper, to get stronger…

High Energy Astrophysical Phenomena · Physics 2023-03-01 Longhua Qin , Jiancheng Wang , Quangui Gao , Weiwei Na , Huaizhen Li , Ao Wang , Chuyuan Yang , Jianping Yang

Very high energy (VHE, E > 30 GeV) gamma-rays are absorbed via interaction with low-energy photons from the extragalactic background light (EBL) if the involved photon energies are above the threshold for electron-positron pair creation.…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-13 D. Mazin

The extragalactic background light (EBL) plays a crucial role in the propagation of high-energy particles throughout the Universe. In this work, we explore the impact of the EBL absorption effect on photon to axionlike particle (ALP)…

High Energy Physics - Phenomenology · Physics 2025-02-19 Hai-Jun Li , Wei Chao , Xiu-Hui Tan , Yu-Feng Zhou

The Extragalactic Background Light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ~10 GeV during propagation from sources at cosmological distances. This…

High Energy Astrophysical Phenomena · Physics 2015-05-18 The Fermi LAT , the GBM Collaboration , : , A. A. Abdo

The extragalactic background light (EBL) is the radiation accumulated through the history of the Universe in the wavelength range from the ultraviolet to the far infrared. Local foregrounds make the direct measurement of the diffuse EBL…

This study investigates the impact of the fluctuations in the extra galactic background light (EBL) on the attenuation of the hard $\gamma$-ray spectra of distant blazars. EBL fluctuations occur on the scales up to 100 Mpc and are caused by…

High Energy Astrophysical Phenomena · Physics 2017-03-22 A. M. Kudoda , A. Faltenbacher

The redshift ($z$) evolution of the Extragalactic Background Light (EBL) photon density is very important to understand the history of cosmological structure formation of galaxies and stars since the epoch of recombination. The EBL photons…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-23 K. K. Singh , K. K. Yadav , P. J. Meintjes
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