| The Seyfert galaxy NGC 4151 is one of the nearest (z=0.00332, D=13.2 Mpc when a Hubble constant of 75 km s-1Mpc-1 is used) and brightest Seyfert 1 galaxies. The host galaxy of NGC 4151 is a typical spiral galaxy SABab (Perez Garcia et al. 1998). It is also one of the best studied objects across the entire electromagnetic spectrum owing to its brightness and variability properties and can be used to test various theoretical models.In the present thesis, we summarized the basic properties about the active galactic nuclei (AGNs) and reviewed the present development of the Seyfert galaxy NGC 4151. We also described the process of the CCD observation and the parameters used in the data processing of NGC 4151. We can get some important physical parameters of the objects using CCD photometry, such as the light curve, the visual magnitude, the color index, the timescale of variability, and so on. We can go on further studying of the physical property, the physical model, the dynamical property, and the evolution process of the objects deeply by analyzing the results derived from CCD photometry. So CCD photometry plays an important role in the development of Astrophysics.When we used the IRAF software package to process the observation data on 2003 May 2, a possible microvariation was found simultaneously in the three bands. Consequently, some possible mechanisms were given to explain the microvariation. If the microvariation is due to a hot spot on the accretion disk, then we can use the variability timescale to calculate the black hole mass of central engine. We compiled the recent photometric and CCD observation data from 1968 to 2003 on the V band and the raw photometric data on the B band from 1910 to 2000. Both the Jurkevich method and the DCF method were adopted to calculate the period of NGC 4151. The results derived by the two methods are consistent with each other. At the same time the long-term variability mechanisms were also discussed. Finally the colour index of... |
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