Microlensing in the double quasar SBS1520+530
  We present the results of a monitoring campaign of the double quasar SBS1520+530 at Maidanak observatory from April 2003 to August 2004. We obtained light curves in V and R filters that show small-amplitude \Delta m~0.1 mag intrinsic variations of the quasar on time scales of about 100 days. The data set is consistent with the previously determined time delay of \Delta t=(130+-3) days by Burud et al. (2002). We find that the time delay corrected magnitude difference between the quasar images is now larger by (0.14+-0.03) mag than during the observations by Burud et al. (2002). This confirms the presence of gravitational microlensing variations in this system. 
E. R. Gaynullina (1), R. W. Schmidt (2), T. Akhunov (1,3), O.   Burkhonov (3), S. Gottloeber (4), K. Mirtadjieva (1,3), S. N...