Related papers: Deciphering Contributions to the Extragalactic Gam…
The extragalactic background light (EBL) contains all the radiation emitted by nuclear and accretion processes since the epoch of recombination. Direct measurements of the EBL in the near-IR to mid-IR waveband are extremely difficult due…
We compute the contribution of blazars (Flat Spectrum Radio Quasars and BL-Lacs) to the Fermi-LAT Extragalactic gamma-ray Background, assuming a gamma-ray luminosity function proportional to the luminosity function of radio galaxies and the…
We present a model for estimating the blazar contribution to the extragalactic gamma-ray background (EGRB) in the EGRET energy range. It is based on inverse-Compton scattering as the dominant gamma-ray production process in the jets of flat…
Very-high-energy (VHE, E \gtrsim 100 GeV) gamma rays emitted by extragalactic sources, such as blazars, initiate electromagnetic cascades in the intergalactic medium. The cascade photons arrive at the earth with angular and temporal…
We describe the properties of the blazars detected by EGRET and summarize the results on the calculations of the evolution and luminosity function of these sources. Of the large number of possible origins of extragalactic diffuse gamma-ray…
We discuss how measurements of the absorption of gamma-rays from GeV to TeV energies via pair production on the extragalactic background light (EBL) can probe important issues in galaxy formation. Semi-analytic models (SAMs) of galaxy…
A gamma-ray burst (GRB) jet running into an external medium is expected to generate luminous GeV-TeV emission lasting from minutes to several hours. The high-energy emission results from inverse Compton upscattering of prompt and afterglow…
Diffuse Galactic gamma-ray emission is produced in interactions of cosmic rays with gas and ambient photon fields and thus provides us with an indirect measurement of cosmic rays in various locations in the Galaxy. The diffuse gamma-ray…
The cosmic gamma-ray background radiation is one of the most fundamental observables in the gamma-ray band. Although the origin of the cosmic gamma-ray background radiation has been a mystery for a long time, the Fermi gamma-ray space…
The spectral shape of the unresolved emission from different classes of gamma-ray emitters can be used to disentangle the contributions from these populations to the extragalactic gamma-ray background (EGRB). We present a calculation of the…
Neutrinos at energies ranging from sub-TeV to EeV from astrophysical sources can yield interesting physical information about fundamental interactions, about cosmic rays and about the nature of the sources and their environment. Gamma-ray…
One of the principal results obtained by the Compton Gamma Ray Observatory relating to the study of gamma-ray bursts was the detection by the EGRET instrument of energetic ($>$100 MeV) photons from a handful of bright bursts. The most…
Very high-energy gamma-ray emission from PKS 0447-439 was detected with the H.E.S.S. Cherenkov telescope array in December 2009. This blazar is one of the brightest extragalactic objects in the Fermi Bright Source List and has a hard…
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…
Very high energy photons from cosmological gamma-ray bursts (GRBs) are expected to interact with extragalactic background light (EBL) and produce electron-positron pairs when they propagate through intergalactic medium (IGM). These…
In addition to its relevant astrophysical and cosmological significance, the Extragalactic Background Light (EBL) is a fundamental source of opacity for cosmic high energy photons, as well as a limitation for the propagation of high-energy…
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…
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…
In this chapter, we discuss the contributions of gamma-ray astronomy at TeV energies to our understanding of the visible content and structure of the universe. We start from the present epoch with the second most intense electromagnetic…
A majority of the $\gamma$-ray emission from star-forming galaxies is generated by the interaction of high-energy cosmic rays with the interstellar gas and radiation fields. Star-forming galaxies are expected to contribute to both the…