Publications by authors named "William W Craig"
Article Synopsis
- The Galactic Centre features a unique group of young, massive stars near the supermassive black hole, Sagittarius A*, raising questions about stellar formation there.
- Previous research argued that soft X-ray emissions in the area are largely from accreting white dwarf systems, but limitations in detection technology have hindered the observation of hard X-ray emissions.
- New findings reveal a concentrated hard-X-ray emission in a small region, suggesting complex interactions involving more massive accreting white dwarfs, low-mass X-ray binaries, or new types of particle interactions, challenging our understanding of stellar evolution and cosmic phenomena in that region.
We have developed a new depth-graded multilayer system comprising W and SiC layers, suitable for use as hard x-ray reflective coatings operating in the energy range 100-200 keV. Grazing-incidence x-ray reflectance at E = 8 keV was used to characterize the interface widths, as well as the temporal and thermal stability in both periodic and depth-graded W/SiC structures, whereas synchrotron radiation was used to measure the hard x-ray reflectance of a depth-graded multilayer designed specifically for use in the range E approximately 150-170 keV. We have modeled the hard x-ray reflectance using newly derived optical constants, which we determined from reflectance versus incidence angle measurements also made using synchrotron radiation, in the range E = 120-180 keV.
View Article and Find Full Text PDFWe describe a technology to mass-produce ultrathin mirror substrates for x-ray telescopes of near Wolter-I geometry. Thermal glass forming is a low-cost method to produce high-throughput, spaceborne x-ray mirrors for the 0.1-200-keV energy band.
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