Related papers: Evolving Stellar Background Radiation and Gamma-Ra…
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…
I report on progress in my ongoing work with Professor Jayant Murthy concerning the origin and nature of the diffuse ultraviolet background radiation over the sky. We have obtained and are reducing a vast trove of Voyager ultraviolet…
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) contains important information about stellar and galaxy evolution. It leaves imprint on the very high energy $\gamma$-ray spectra from sources at cosmological distances due to the process of pair…
We examine the effect of gamma-ray absorption by the extragalactic infrared radiation on intrinsic spectra predicted for 1ES0229+200 and compare our results with the observational data. We find agreement with our previous results on the…
The diffuse flux of cosmic neutrinos has been measured by the IceCube Observatory from TeV to PeV energies. We show that an improved characterization of this flux at the lower energies, TeV and sub-TeV, reveals important information on the…
I review recent observational and theoretical progress in our understanding of the cosmic evolution of luminous sources. Through a combination of deep imaging, Keck spectroscopy, and COBE background measurements, important constraints have…
We assess the constraints imposed by the observed extragalactic background light (EBL) on the cosmic history of star formation and the stellar mass density today. The logarithmic slope of the galaxy number-magnitude relation from the…
New deep optical and near-infrared imaging is combined with archival ultraviolet and infrared data for fifteen nearby galaxies mapped in the Spitzer Extended Disk Galaxy Exploration Science survey. These images are particularly deep and…
The attenuation produced by extragalactic background light (EBL) in $\gamma$-ray spectra of blazars has been used to constrain the Hubble constant ($H_0$) and matter density ($\Omega_{\rm m}$) of the Universe. We propose to estimate $H_0$…
We present a new evolutionary model for the far-UV to sub-mm properties of the galaxy population. This combines a semi-analytic galaxy formation model based on hierarchical clustering (GALFORM) with a spectro-photometric code which includes…
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…
Direct measurements of the extragalactic background light (EBL) in the near-IR to mid-IR waveband are extremely difficult due to an overwhelming foreground from the zodiacal light that outshines the faint cosmological diffuse radiation…
The universe is filled with a diffuse and isotropic extragalactic background of gamma-ray radiation, containing roughly equal energy flux per decade in photon energy between 3 MeV-100 GeV. The origin of this background is one of the…
The large-scale diffuse $\gamma-$ray flux observed by Fermi-LAT in the 1-100 GeV energy range, parameterized as $\propto E^{-\Gamma}$, has a spectral index $\Gamma$ that depends on the distance from the Galactic center. This feature, if…
The total extragalactic background radiation can be an important test of the global star formation history (SFH). Using direct observational estimates of the SFH, along with standard assumptions about the initial mass function (IMF), we…
We consider nebulae which are created around binary systems containing rotation powered pulsars and companion stars with strong stellar winds. It is proposed that the stellar and pulsar winds have to mix at some distance from the binary…
The attenuation of high-energy gamma-ray spectrum due to the electron-positron pair production against the extragalactic background light (EBL) provides an indirect method to measure the EBL of the universe. We use the measurements of the…
The energy spectra of TeV gamma-rays from blazars, after being corrected for intergalatic absorption in the Extragalactic Background Light (EBL), appear unusually hard, a fact that poses challenges to the conventional models of particle…
Recent observations of TeV gamma rays from distant sources provide new limits on the cosmic infrared background and thus on radiative decays of background neutrinos. I translate these limits into bounds on transition dipole moments and…