Related papers: Limits on the extragalactic background light in th…
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…
We describe a new method for measuring the extragalactic background light (EBL) through the detection of $\gamma$-ray inverse Compton (IC) emission due to scattering of the EBL photons off relativistic electrons in the lobes of radio…
The very high energy (VHE) $\gamma$-ray spectra of some TeV Blazars, after being corrected for absorption in the extragalactic background light (EBL), appear unusually hard, which poses challenges to conventional acceleration and emission…
Our goal is to limit the redshifts of three blazars PG 1553+113, 3C 66A and PKS 1424+240, through the investigation of their Fermi and VHE (very high energy) $\gamma$-ray observations. We assume that the intrinsic spectra of PG 1553+113, 3C…
(Abridged) Statistical analysis of the unresolved light in the Hubble Deep Field (HDF) strongly constrains possible sources of the optical Extragalactic Background Light (EBL). To test for the statistical signature of previously undetected…
We have previously calculated the intergalactic background light (IBL) as a function of redshift in the far ultraviolet to near infrared range, based purely on data from deep galaxy surveys. Here we utilize similar methods to determine the…
The study of the extragalactic background light (EBL) in the optical and near infrared has received a lot of attention in the last decade, especially near a wavelength of $\lambda\approx 3.4\operatorname{\mu m}$, with remaining tension…
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 Extragalactic Background Light (EBL) at UV, optical and NIR wavelengths consists of the integrated light of all unresolved galaxies along the line of sight plus any contributions by intergalactic matter including hypothetical decaying…
We study the possible detection of and properties of very high-energy (VHE) gamma-ray emission (in the energy band above 100 GeV) from high redshift sources. We report on the detection of VHE gamma-ray flux from blazars with redshifts…
The extragalactic background light records the history of infrared, optical and ultraviolet light radiation including re-radiation since the epoch of reionization. While challenging to measure directly, it can be measured indirectly via its…
The intrinsic BL Lac spectra above few hundreds GeV can be very different from the observed ones due to the absorption effects by the diffuse Extragalactic Background Light (EBL), at present poorly known. With the recent results, there are…
The imprint of cosmic backgrounds in the gamma ray spectra of blazars has recently been detected by H.E.S.S. and Fermi-LAT, opening the way to studies of gamma-ray propagation on cosmological scales. This proceeding discusses the current…
The extragalactic background light (EBL) consists of integrated light from all sources of emission throughout the history of the universe. At near-infrared wavelengths, the EBL is dominated by stellar emission across cosmic time; however,…
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…
1ES 0414+009 (z = 0.287) is a distant high-frequency-peaked BL Lac object, and has long been considered a likely emitter of very-high energy (VHE, E>100 GeV) gamma-rays due to its high X-ray and radio flux. Observations in the VHE gamma-ray…
Fermi-LAT spectra at high energies (HE, 0.1-100 GeV) are often extrapolated to very high energies (VHE, >100 GeV) and considered either a good estimate or an upper limit for the blazars intrinsic VHE spectrum. This assumption seems not well…
Extreme high-energy peaked BL Lac objects (EHBLs) are an emerging class of blazars with exceptional spectral properties. The non-thermal emission of the relativistic jet peaks in the spectral energy distribution (SED) plot with the…
Joint observations of extreme blazars with Fermi Large Area Telescope (LAT) and Imaging Atmospheric Cherenkov telescopes (IACT) have been previously used to derive lower bounds on intergalactic magnetic field (IGMF). We update these…
The Fermi Gamma-ray Observatory discovered about a thousand extragalactic sources emitting energy from 100 MeV to 100 GeV. The majority of these sources belong to the class of blazars characterized by a quasi-featureless optical spectrum…