Related papers: Optical depth for VHE gamma-rays from distant sour…
Very high energy (VHE; $E \geq$ 100GeV) $\gamma-$ray from cosmological distances are attenuated by the extragalactic background light (EBL) in the IR to UV band. By contrasting measured versus intrinsic emission, the EBL photon density can…
Very high energy (VHE, energy >~ 100 GeV) {\gamma}-rays undergo pair production with photons of the extragalactic background light (EBL). Thus, the intrinsic {\gamma}-ray flux of cosmological sources is attenuated and the Universe should be…
The Extragalactic Background Light (EBL) from the infrared (IR) through the ultraviolet (UV) is dominated by emission from stars, either directly or through absorption and reradiation by dust. It can thus give information on the star…
TeV gamma rays from distant astrophysical sources are attenuated due to electron-positron pair creation by interacting with ultraviolet/optical to infrared photons which fill the universe and are collectively known as the extra-galactic…
The extragalactic background Light (EBL) from ultraviolet to infrared comprises the emission from all stars, galaxies, and actively accreting black holes in the observable Universe. A precise measurement of the EBL is critically important…
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…
Ground-based observatories have been collecting 0.2 - 20 TeV gamma rays from blazars for about twenty years. These gamma rays can experience absorption along the line of sight due to interactions with the extragalactic background light…
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…
We re-derive the possible dependence of the redshift with very high energy (VHE) $\gamma$-ray photon index. The results suggest that the universe to VHE $\gamma$-rays is becoming more transparent than usually expected. We introduce the…
The extragalactic background light (EBL), from ultraviolet to infrared wavelengths, is predominantly due to emission from stars, accreting black holes and reprocessed light due to Galactic dust. The EBL can be studied through the imprint it…
The extragalactic background light (EBL) is of fundamental importance both for understanding the entire process of galaxy evolution and for gamma-ray astronomy. However, the overall spectrum of the EBL between 0.1 and 1000 microns has never…
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…
Aims: Our aim is to study the production mechanism for very-high-energy (VHE; >100GeV) gamma-rays in distant active galactic nuclei (AGN) and use the observed VHE spectrum to derive limits on the Extragalactic Background Light (EBL). We…
Our goal is to research the upper limits on the extragalactic background light (EBL). The upper limits on the extragalactic background light (EBL), using the Fermi and very high energy (VHE) spectra recently observed in TeV blazars, are…
We present new synthesis models of the extragalactic background light (EBL) from far infra-red (FIR) to TeV gamma-rays, with an emphasis on the extreme ultraviolet (UV) background which is responsible for the observed ionization and thermal…
The Extragalactic Background Light (EBL) is the accumulated light produced throughout the universe history, spanning the UV, optical, and IR spectral ranges and mostly originating from stars, directly or re-processed by dust. However,…
The intensity of the extragalactic background (EBL), the accumulated optical and infrared emissions since the first stars, is the subject of a decades-long tension in the optical band. These photons form a target field that attenuates the…
Extragalactic background light (EBL) plays an important role in cosmology since it traces the history of galaxy formation and evolution. Such diffuse radiation from near-UV to far-infrared wavelengths can interact with $\gamma$-rays from…
We study the origin of the extragalactic diffuse gamma-ray background using the data from the Fermi telescope. To estimate the background level, we count photons at high Galactic latitudes |b|>60 degrees. Subtracting photons associated to…
In this work, we use two different methods to determine the opacity of the TeV gamma-rays caused by the extragalactic background light (EBL) via e-e+ production due to photon-photon interaction. The first method, Model-Dependent Approach,…