We have analyzed the long pointed observations of the Z sources in the Rossi X-Ray Timing Explorer (RXTE) public archive to study the high energy emission in those sources. Our analysis is concentrated on the High Energy X–Ray Timing Experiment (HEXTE) waveband, since we are primarily interested in studying the hard X– ray (i.e., E > 20 keV) production in those sources. We give here the prelimi...

We describe X-ray production in the atmospheres of hot, early-type stars in the framework of a “stochastic shock model”. The extended envelope of a star is assumed to possess numerous X-ray emitting “hot” zones that are produced by shocks and embedded in the ambient “cold” medium in dynamical equilibrium. It is shown that the apparent lack of X-ray variability on short (∼ hours) timescales do n...

Yohkoh observed strong gamma-ray emission from a flare (X9.4/2B) on November 6, 1997. The emission was impulsive and lasted for about 4 min (11:52-11:56 UT). The spectrum exhibits gamma-ray lines and extends up to a few tens of MeV The Oriented Scintillation Spectrometer Experiment (OSSE) on board the Compton Gamma-Ray Observatory (CGRO) missed the peak phase of gamma-ray flare but detected sig...

in the present work, we report a suitable approach for the preparation of batio3 nanostructures via the hydrothermal condition using dolapix et85 as surfactant. the powders were investigated by x-ray diffraction (xrd), scanning election microscopy (sem), energy-dispersive x-ray spectroscopy (edax), field emission transmission electron microscopy (fetem), selected area electron diffraction (saed...

The purpose is to review in a 4-part series: (i) the basic principles of x-ray production, (ii) x-ray interactions and data capture/conversion, (iii) acquisition/creation of the CT image, and (iv) operational details of a modern multislice CT scanner integrated with a PET scanner. In part 1, the production and characteristics of x-rays were reviewed. In this article, the principles of x-ray int...

Accreting Black Holes (BHs) are believed to be sites of possible particle acceleration with favorable conditions also for effective gamma-ray production. However, because of photon-photon pair production, only low energy (MeV) gamma-rays can escape these compact objects with typically very large compactness parameter, κ = L L Edd Rg R ≥ 0.01, given that in most cases the accretion disks within ...

We present a broad overview of the principal processes and astrophysical sites of gamma-ray line production and review the main pre-INTEGRAL satellite observations to set the stage to the next European era of gamma-ray line astronomy.