simulation of gamma and hadron showers in the energy range 100gev- 25tev has been carried out. for a big ideal cherenkov light array, characteristics of lateral distribution of cherenkov photon density have been studied. results from this ideal detector are compared with those simulated for a real tunka- like array to investigate experimental potential of using existence of a hump in lateral di...

background: natural radioactivity in materials under certain conditions can reach the hazardous radiological levels. so, it becomes necessary to study the natural radioactivity in different materials to assess the dose for the population in order to know the health risks and to have a baseline for future changes in the environmental radioactivity due to human activities. materials and methods: ...

Detection of γ-ray emission from a class of active galactic nuclei (viz blazars), has been one of the important findings from the Compton Gamma Ray Observatory (CGRO). However, their γ-ray luminosity function has not been well determined. Few attempts have been made in earlier works, where BL Lacs and Flat Spectrum Radio Quasars (FSRQs) have been considered as a single source class. In this pap...

Background: The existence of some radionuclides in soil and some building materials produce a β-γ radiation field, which in some regions the exposure of these radionuclides to human is high. Materials and Methods: The air-absorbed dose, indoor and outdoor annual effective dose of soil and some building material samples (ceramic, granite, gypsum, etc.). The samples were collected from 3...

Globular clusters (GCs) are emerging as a new class of γ-ray emitters, thanks to the data obtained from the Fermi Gamma-ray Space Telescope. By now, eight GCs are known to emit γ-rays at energies >100 MeV. Based on the stellar encounter rate of the GCs, we identify potential γ-ray emitting GCs out of all known GCs that have not been studied in details before. In this paper, we report the discov...

We study the γ-ray emission properties of pulsars by using a new selfconsistent outer gap model. The outer gap can exist in pulsars with age over million years old if the effect of magnetic inclination angle as well as the average properties of the outer gap are considered. The mature γ-ray pulsars, whose ages are between 0.3 to 3 million years old, are able to move up to high galactic latitude...

We consider high energy γ-ray radiation from the radio pulsars associated with some unidentified EGRET γ-ray sources. Calculated efficiencies for the conversion of spin-down power to γ-rays and the energy spectra of the high energy γ-rays from these possible γ-ray pulsars in outer gap models are compared with observed results. Of these possible γ-ray pulsars, our results indicate that (i) PSR B...