Mapping of the neutron star X-ray binary X1822-371

We report the results of optical/X-ray observations of X-ray binaries with 0.1 second time resolution. The analysis shows evidence of a variability timescales in this largely unexplored time domain in the optical as well as and the correlation between the two energy bands. We also report the physical constraints on the system geometry and the driving mechanism behind optical flickering and quasi-periodic oscillations in the accretion disk. In addition, light curves binned over the orbital cycle and fitted to 3-dimensional binary models using maximum entropy statistics in order to reconstruct the vertical structure of the accretion disk without invoking any pre-assumptions for the disk's vertical profile.