MAXI-GSC detection of a sudden drop in X-ray intensity from GX 13+1

MAXI-GSC detected a sudden drop in X-ray intensity from the low-mass X-ray binary GX 13+1 on August 30, 2014. Base on the on-demand analysis, the 2-10 keV flux once decreased from 0.97+-0.04 photons/s/cm2, which was the average one at 7 scan transits from 01:20 to 10:37 UT on August 30, to 0.31+-0.07 photons/s/cm2 at the scan transit at 12:10, and recovered to 0.87+-0.10 photons/s/cm2 at 13:43.