Related papers: Constraining Extragalactic Background Light From T…
Prompted by the increasing interest of axion-like particles (ALPs) for very-high-energy (VHE) astrophysics, we have considered a full scenario for the propagation of a VHE photon/ALP beam emitted by a BL Lac and reaching us in the light of…
Extreme TeV blazars (ETBs) are active galactic nuclei with jets presumably pointing towards the observer having their intrinsic spectral energy distributions (SEDs) peaked at an energy in excess of 1 TeV. These sources typically reveal…
The Fermi gamma-ray space telescope has revolutionized our understanding of the cosmic gamma-ray background radiation in the GeV band. However, investigation on the cosmic TeV gamma-ray background radiation still remains sparse. Here, we…
In February-March 2014, the MAGIC telescopes observed the high-frequency peaked BL Lac 1ES 1011+496 (z=0.212) in flaring state at very-high energy (VHE, E>100GeV). The flux reached a level more than 10 times higher than any previously…
The High Energy Stereoscopic System (H.E.S.S.) experiment, a ground-based gamma-ray Cherenkov telescope array located in Namibia, has now detected many extragalactic objects, which redshifts range from z=0.00183 up to z=0.2, possibly more.…
AIMS: To investigate the very high energy (VHE: >100 GeV) gamma-ray emission from the high-frequency peaked BL Lac 1ES 0229+200. METHODS: Observations of 1ES 0229+200 at energies above 580 GeV were performed with the High Energy…
In this paper, we compile the very-high-energy and high-energy spectral indices of 43 BL Lac objects from the literature. Based on a simple math model, $\Delta\Gamma_{obs}=\alpha {\rm{z}}+\beta $, we present evidence for the origin of an…
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…
If dark matter is unstable and the mass is within GeV-TeV regime, its decays produce high-energy photons that give contribution to the extragalactic gamma-ray background (EGRB). We constrain dark matter decay by analyzing the 50-month EGRB…
I review the constraints imposed by the observed extragalactic background light (EBL) on the history of the stellar birthrate in galaxies. At faint magnitudes, the logarithmic slope of the galaxy counts is flatter than 0.4 in all seven…
The present day spectrum of the extragalactic background light (EBL) in UV, optical and IR wavelengths is the integral result of multiple astrophysical processes going on throughout the evolution of the Universe. The relevant processes…
We use the new results of the HEGRA detector on the TeV gamma-ray emission from MKN 501 to set upper limits on the energy density of the cosmic infrared background (CIRB). Contrary to previous interpretations of the gamma-ray spectrum of…
We present models of the extragalactic background light (EBL) based on several scenarios of galaxy formation and evolution. We have treated galaxy formation with the Press-Schecter approximation for both cold dark matter (CDM) and cold+hot…
The 1 - 5 micron diffuse sky emission from which local foreground emission from the solar system and the Galaxy have been subtracted exceeds the brightness that can be attributed to normal star forming galaxies. The nature of this excess…
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…
We present an updated model for the extragalactic background light (EBL) from stars and dust, over wavelengths approximately 0.1 to 1000 $\mu$m. This model uses accurate theoretical stellar spectra, and tracks the evolution of star…
The study of the extragalactic background light (EBL) is undergoing a renaissance. New results from very high energy experiments and deep space missions have broken the deadlock between the contradictory measurements in the optical and…
The intergalactic magnetic field (IGMF) in cosmic voids can be indirectly probed through its effect on electromagnetic cascades initiated by a source of TeV gamma rays, such as blazars, a subclass of active galactic nuclei. Blazars that are…
(Abridged) We present the first detections of the mean flux of the optical extragalactic background light (EBL) at 3000, 5500, and 8000A. Diffuse foreground flux at these wavelengths comes from terrestrial airglow, dust-scattered sunlight…
Attenuation of the TeV gamma-ray flux from distant blazars through pair production with extragalactic background light leads to the development of electromagnetic cascades and subsequent, lower energy, GeV secondary gamma-ray emission. Due…