An X-ray microlensing test of AU-scale quasar disk structure Original Research Article

The innermostregion of quasars can be resolved by microlensing on scales down to a few AU. For this purpose, X-rays originating from the innermost regions can be selectively amplified by microlensing resulting from the “caustic crossing” events, and observations at X-ray bands are most preferable. If the observation has been done, lower limits of black hole mass will be determined, because information about gravitational potential of the black hole which is surrounded by accretion disk will be obtained.