We report the detection using data from the Advanced Satellite for Cosmology and Astrophysics (ASCA ) of a hard X-ray source in the vicinity of the radio pulsar PSR B1853+01, which is located within the supernova remnant (SNR) W44. PSR B1853+01, a 267 ms pulsar, has to date been detected only in the radio band. Previous observations at soft X-ray energies (e.g., with ROSAT HRI) have failed to d...

We examine the X-ray spectral and temporal behavior of the Galactic black hole candidate source GRS 1915+105 during its spectral state transition observed in 1997 March-August. The source was making a slow transition from a low-hard state to a high-soft state in about three months and during this transition it was exhibiting a series of fast variations which can be classified as bursts. During ...

At the SPring-8 storage ring, we have recently developed two X-ray instruments for emittance diagnostics. The one for a bending magnet source is the X-ray pinhole camera which directly images the beam profile. A pinhole in the atmosphere is composed of combined narrow X-Y slits made of tungsten. A scintillator crystal is used to convert the X-ray beam image to a visible image. The spatial resol...

We report the results of BeppoSAX and ASCA observations of the X–ray source 1E 1743.1–2843, located in the region of the galactic center, performed between 1993 and 1998. Observations spanning almost twenty years show that 1E 1743.1–2843 is a persistent X–ray source, most likely powered by accretion onto a compact galactic object. The absence of periodic pulsations and the relatively soft X–ray...

The short interval between successive outbursts of RS Oph strongly suggests that it has a high mass white dwarf accreting at a high rate. This, in turn, suggests the possibility of prominent X-ray emission from RS Oph in quiescence. However, archival quiescent X-ray observations of RS Oph show it to be a modest soft X-ray source but not a strong 2–10 keV X-ray source. In this aspect, RS Oph dif...

We report the results of BeppoSAX and ASCA observations of the X–ray source 1E 1743.1–2843, located in the region of the galactic center, performed between 1993 and 1998. Observations spanning almost twenty years show that 1E 1743.1–2843 is a persistent X–ray source, most likely powered by accretion onto a compact galactic object. The absence of periodic pulsations and the relatively soft X–ray...

Beamline 10.3.2 at the ALS is a bend-magnet line designed mostly for work on environmental problems involving heavy-metal speciation and location. It offers a unique combination of X-ray fluorescence mapping, X-ray microspectroscopy and micro-X-ray diffraction. The optics allow the user to trade spot size for flux in a size range of 5-17 microm in an energy range of 3-17 keV. The focusing uses ...

The nearby galaxy M33 hosts the most luminous steady X-ray source in the Local Group. The high spatial resolution of Chandra allows us to confirm that this ultra-luminous X-ray source is within the nucleus and rule out at the 4.6σ level a previously proposed possible counterpart located 1 away. The X-ray spectrum is well fitted by a disc blackbody with kTin=1.18±0.02 keV and Rin(cos θ)=57±3 km,...

We derive an X-ray luminosity function for active galactic nuclei (AGN) that accounts for the X-ray source counts in the 0.5–2.0 and 2–10 keV energy ranges, the redshift distribution of AGNs in the ROSAT Deep Survey (RDS), as well as the X-ray background (XRB) from 1–10 keV. We emphasize the role of X-ray absorption, which has a large effect on the faint end of the 2– 10 keV source counts, as w...