Study On The Jet Trajectory Of The Bl Lac Object 0735+178

BL Lac object 0735+178 showed a straight jet trajectory up still the mid 1992, however a twisted jet with apparent superluminal motion and two sharp apparent bends of 90 o within two milliarcseconds of the core was observed between the mid 1995 and mid 1998. A non-ballistic model is used to fit the amazing observation results in this thesis, and a rectilinear trajectory will be appeared once more between 2000 and 2002 by the non-ballistic model, which is in accord with the observation in the frequencies of 15.335GHZ and 15.365GHZ.. The main work in this thesis is summarized as follows:Firstly, we discuss the formation and radiation mechanism of the jet in chapter 2. The acceleration and the collimation mechanisms are introduced mostly as parts of the formation of the jet in the beginning; We also introduce two most important radiation mechanisms—the synchrotron radiation and the inverse-compton scatter subsequently.Secondly, the jet precession and the apparent superluminal motion of jet in the active galactic nucle(iAGN) are discussed in chapter 3. We introduce the disk-driven precession mechanism and the Lense-Thirring precession mechanism in brief. As the apparent superluminal motion is a hotspot on the study of jet in the AGN, so we introduce the ballistic model and the non-ballistic model in particular,besides, we also compare two model in this thesis.Finally, we fit the changes of jet trajectory in BL Lac object 0735+178,which is our primary work in this thesis. Then, we also can forecast the jet trajectory by the non-ballistic model, which need to be tested by the observation in future.