We report the discovery of spatially-extended, non-thermal-like emission components in Chandra X-ray spectra for five of a sample of seven massive, merging galaxy clusters with powerful radio halos. The emission components can be fitted by power-law models with mean photon indices in the range 1.5 < Γ < 2.0. A control sample of regular, dynamically relaxed clusters, without radio halos but with...

Chandra observations of the type 1.8, low-redshift (z 1⁄4 0:115), red (J KS 2) quasar 2MASSJ 104943+583750 (2M1049+5837) indicated an unusually hardX-ray spectrum (HR 0:6), suggesting obscuration ofNH 4 ; 10 cm 2 and a flat 0:4 power-law slope. A higher signal-to-noise ratio XMM-Newton observation reported here reveals a more complex spectrum, being extremely hard above 2 keV, 0:6, with a well-...

Terasawa reported strong X-ray emission from charged-up insulators, and proposed an X-ray production device only using the electrification. We constructed a similar device and studied the conditions of X-ray emission. It was shown that X-rays could be produced without supplying electrons from a filament.

X-ray emission has been achieved using an electron beam generated by a pseudospark low-pressure discharge and utilised as a diagnostic for beam detection. A 300 A, 34 kV PS-sourced electron beam pulse of 3 mm diameter impacting on a 0.1 mm-thick molybdenum target generated X-rays which were detected via the use of a small, portable X-ray detector. Clear X-ray images of a micro-sized object were...

We study the possibility that an extended cosmic-ray leptonic and/or hadronic halo is at origin of large-scale gamma-ray emission detected from Andromeda Galaxy (M31). consider a broad ensemble non-homogeneous diffusion scenarios and injection sources. find electrons protons could be, very likely are, responsible for part, or all, M31, including out to more than 100 kpc center galaxy. also simu...

With the successful launch of the Swift Gamma-ray Burst Explorer, a rich trove of early X-ray afterglow data has been collected by its on-board X-Ray Telescope (XRT). Some interesting features are emerging, including a distinct rapidly decaying component preceding the conventional afterglow component in many sources, a shallow decay component before the more “normal” decay component observed in...

Jet models for the high-energy emission of Galactic X-ray binary sources have regained significant interest with detailed spectral and timing studies of the X-ray emission from microquasars, the recent detection by the HESS collaboration of very-high-energy $\gamma$-rays from the microquasar LS~5039, and the earlier suggestion of jet models for ultraluminous X-ray sources observed in many nearb...