Using the first three and a half years of observations from the Energetic Gamma Ray Telescope (EGRET) on board the Compton Gamma Ray Observatory (CGRO), phase-resolved analyses are performed on the emission from the three brightest highenergy γ-ray pulsars, Crab, Geminga, and Vela. For each pulsar, it is found that there is detectable high-energy γ-ray emission above the galactic diffuse backgr...

It is generally assumed that the flux of cosmic-rays observed at the top of the Earth’s atmosphere is representative of the flux in the Galaxy at large. The advent of high sensitivity, high resolution γ-ray detectors, together with a knowledge of the distribution of the atomic hydrogen and especially of the molecular hydrogen in the Galaxy on sub-degree scales, as provided by the NANTEN survey,...

Synthesis of organic compounds using nano-catalysts is more and more attention due to the numerous advantages such as cost-effectiveness, high catalytic activity, ease of product separation, recovery of the catalyst, repeated recycling potential and good stability. In this work, TiCl2/nano-γ-Al2O3, as a novel type of green heterogeneous solid acid was prepared by the immobilization of TiCl2 on ...

The Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT) is the first realization of a liquid xenon time projection chamber for Compton imaging of MeV γ-ray sources in astrophysics. By measuring the energy deposit and the three spatial coordinates of individual γ-ray scattering points, the location of the source in the sky is inferred with Compton kinematics reconstruction. The angular resolution...

TeV γ-ray emission has been recently discovered by Cherenkov telescopes from two microquasars, LS 5039 and LS I +61303. This emission is likely to be produced inside the binary system since in both cases variability with the orbital period of the binary has been discovered. In fact, such emission features have been recently predicted by the inverse Compton (IC) e pair cascade model. In this mod...

Blazars exhibit flares across the entire electromagnetic spectrum. Many γ-ray flares are highly correlated with flares detected at longer wavelengths; however, a small subset appears to occur in isolation, with little or no correlated variability at longer wavelengths. These “orphan” γ-ray flares challenge current models of blazar variability, most of which are unable to reproduce this type of ...

Until now, solar γ-ray and neutron emissions have only been detected during times of intense solar activity, specifically, during solar flares. These emissions arise from the interaction of accelerated solar particles (both electrons and ions) with the ambient solar material. However, there are several reasons to expect that γ-ray emission might also be detectable at times when there is no sign...

The discovery of multiband afterglows definitely shows that most γ-ray bursts are of cosmological origin. γ-ray bursts are found to be one of the most violent explosive phenomena in the Universe, in which astonishing ultra-relativistic motions are involved. In this article, the multiband observational characteristics of γ-ray bursts and their afterglows are briefly reviewed. The standard model ...

γ Cassiopeia (γ Cas), is known to be a binary system consisting of a Be-type star and a low-mass (M ∼ 1M ) companion of unknown nature orbiting in the Be-disc plane. Here, we apply the quasi-spherical accretion theory on to a compact magnetized star and show that if the low-mass companion of γ Cas is a fast spinning neutron star, the key observational signatures of γ Cas are remarkably well rep...