Gamma-ray emission in the TeV (1012 eV) range has been detected by HESS from two X-ray binaries: PSR B125963 and LS 5039. In both, the early-type star provides large numbers of target photons for pair-production with TeV γ-rays. This results in a modulation of the γ-ray flux as the relative positions of the γ-ray source and companion star change with orbital phase for the observer. The extent t...

We have for the first time detected X-ray emission associated with a protostellar jet, on the jet emanating from the L1551 IRS5 protostar. The IRS5 protostar is hidden behind a very large absorbing column density, making the direct observation of the jet’s emission possible. The observed X-ray emission is likely associated with the shock “working surface”, i.e. the interface between the jet and...

X-ray images and spectra of 5 cataloged supernova remnants (SNRs), G12.0−0.1, G346.6−0.2, G348.5+0.1, G348.7+0.3, and G355.6−0.0, observed in the ASCA galactic plane survey are presented. The sizes of X-ray emission from G12.0−0.1, G348.5+0.1, G348.7+0.3, and G355.6−0.0 are comparable to their radio structures, while that of G346.6−0.2 is smaller than the radio structure. The X-ray spectra of a...

We have for the first time detected X-ray emission associated with a proto-stellar jet, on the jet emanating from L1551 IRS5. The IRS5 proto-star is hidden beyond a very large absorbing column density, making the direct observation of the jet's emission possible. The observed X-ray emission is likely associated with the shock " working surface " , i.e. the interface between the jet and the circ...

We present the first high-resolution, X-ray image of the circumnuclear regions of the Seyfert 1 galaxy NGC 3516, using the Chandra X-ray Observatory (CXO). All three of the CXO observations reported were performed with one of the two grating assemblies in place, and here we restrict our analysis to undispersed photons (i.e. those detected in the zeroth-order). A previously-unknown X-ray source ...

Hydration shells around ions are crucial for many fundamental biological and chemical processes. Their local physicochemical properties are quite different from those of bulk water and hard to probe experimentally. We address this problem by combining soft X-ray spectroscopy using a liquid jet and molecular dynamics (MD) simulations together with ab initio electronic structure calculations to e...

X-ray betatron radiation is produced by oscillations of electrons in the intense focusing field of a laser-plasma accelerator. These hard x-rays show promise for use in femtosecond-scale time-resolved radiography of ultrafast processes. However, the spectral characteristics of betatron radiation have only been inferred from filter pack measurements. In order to achieve higher resolution spectra...

We present optical and X-ray spectra of a radio-quiet X-ray selected AGN, RX J1042+1212 (z=0.271). The hα and hβ emission lines are very broad (with full widths at half maximum of ∼10000 km s) and have double-peaked profiles. Such features are rarely observed in AGN in general but are even more unusual in radio-quiet objects. The analysis of the ROSAT PSPC data reveals a non-varying, unabsorbed...

Observations of two unclassified Low Mass X–ray Binaries, X1543–624 and X1556–605, are presented. In the 2– 10 keV band the first of the two sources is a factor of two stronger than the other. Both sources do not show X–ray bursts, dips or eclipses in their X–ray light curves. We find that both spectra are described by a two–component model consisting of emission from a cool accretion disk plus...

Using ROSAT PSPC data, we have performed several tests aimed at understanding the origin of the soft X-ray spectral component detected from the bulge of M31. We find that a significant soft component in the spectrum of the bulge is spatially correlated with the unresolved X-ray emission near the core of M31, which is probably a hot interstellar medium or perhaps a population of multiple faint s...