INTERACTING BINARIES: Accretion, Evolution, and Outcomes. AIP Conference Proceedings, Volume 797, pp. 365-370 (2005).
Casares, J.; Muñoz-Darias, T.; Martínez-Pais, I. G.; Cornelisse, R.; Charles, P. A.; Marsh, T. R.; Dhillon, V. S.; Steeghs, D.
We present preliminary results of a simultaneous X-ray/optical campaign of the proto-typical LMXB Sco X-1 at 1-10 Hz time resolution. Lightcurves of the high excitation Bowen/HeII emission lines were obtained through narrow interference filters with ULTRACAM, and these were cross-correlated with X-ray lightcurves. We find evidence for correlated variability, in particular when Sco X-1 enters the Flaring Branch. The Bowen/HeII lightcurves lag the X-ray lightcurves with a light travel time which is consistent with reprocessing in the companion star.