| The results of eight VLBA observations at 5 GHz, spanning 3 years, have yielded a measured trigonometric parallax for Scorpius X-1 of 0'' .00036+/-0' ' .0004 corresponding to a distance of 2.8 +/- 0.3 kpc. The accurate parallax for Scorpius X-1 provides the distance measurement necessary for testing a fundamental prediction of the unified theory of low-mass X-ray binaries. The theory predicts that binaries like Scorpius X-1 radiate at the Eddington luminosity and are standard candles when transitioning between the normal and flaring branches of their X-ray color-color diagram.; Detailed models for the accretion and radiation processes taking place in X-ray binaries are important for a clear understanding of these high energy systems.; Flux density variability studies of radio light curves of Scorpius X-1 from Very Large Array observations taken between 1981 to 1990 indicate spatially small radio emission regions. The light curves suggested that the radio emission exhibited preferred timescales of ∼3 hours.; The observation campaign of Scorpius X-1 included four epochs of simultaneous Rossi X-ray Timing Explorer X-ray satellite observations and Very Long Baseline Array radio telescope observations from which milliarcsecond-scale radio maps of Scorpius X-1 were produced.; The X-ray flux data are modeled with additive power law, black body, and Gaussian components to estimate the X-ray luminosity between 2.5--18.2 keV. The X-ray flux was also modeled with an additive bulk-motion Comptonization, black body and Gaussian model, which provides more physical insight into the process of Sco X-1 than a power law additive model.; The evolution of Sco X-1's X-ray QPOs as it transitions through the X-ray states is presented. These QPOs are consistent with a two-oscillator model and are not consistent with other proposed models.; A known distance, the X-ray and radio observations of Scorpius X-1, and previously published optical, infrared, ultraviolet observation results suggest that the Scorpius X-1 binary contains a neutron star partially obscured in the observed line-of-sight by accreting material and a F-class secondary star.; Sco X-1 appears to be a lower-energy Galactic analog of a quasar. It has similar morphology, spectral properties, variability and polarization as quasars. (Abstract shortened by UMI.)... |
