The Properties of the Variation in Luminosity of NGC4051

For making the X-ray observation of the variation in luminosity of Seyfert Galaxy NGC 4051 in cooperation with EXOSAT, after the joint mul-tiband observation carried out in May 1985, the short timescale variation in luminosity of NGC 4051 at B and V wavebands were observed and researched on December 7 and 9, 1985. The main results are as follows.(1) At B waveband, the variations in the luminosity of two short time scales have been obtained. One time scale is 1800s, corresponding to the scale of 1000s at X-ray band. The other is 4200s, corresponding to that of 3600s at X-ray band. The amplitude for the 1800s scale is ΔB≈0.43±0.08mag. (see Figs. 2 and 3). The amplitude for the 4200s scale is ΔB=0.21±0.04mag.(2) there is a short time scale variation in the luminosity at V-band, with a scale of 2400s and the amplitude being ΔV=0.17mag.±0.07(Fig.4).(3) From the observations at X and U wavebands, it is discovered that the timescale of the variation in luminosity of NGC 4051 increases with the wavelength.