BL La天体0735+178喷流轨迹研究.pdf

华中科技大学硕士学位论文
摘要
BL Lac 天体 0735+178 的喷流在 1992 年中期以前呈现一个直线型的轨迹,然而
在 1995 年中期到 1998 年中期却观测到喷流在离核 2mas 距离内有两个明显的九十度
的弯曲结构,并且喷流上存在视超光速运动。本文通过非弹道模型较好的拟合了这
种有趣的现象,并且由该模型得到,喷流轨迹在 2000 年到 2002 年间将又会重新转
变为线性的,这和 和 波段的观测数据很好地吻合了。本文的
工作主要集中在以下几个方面:
首先,本文的第二章讨论了活动星系核中喷流的形成以及辐射机制。关于喷流
的形成部分,主要介绍了喷流的准直和加速机制;关于喷流的辐射机制部分,则是
介绍了喷流两种重要的辐射机制——同步辐射和逆康普顿散射。
其次,本文的第三章讨论了活动星系核中喷流的进动以及视超光速运动。本章
先对喷流的盘进动机制和 Lense-Thirring 进动机制分别加以简要地介绍;视超光速运
动也是活动星系核中喷流研究的热点问题,因此本文详细讨论了弹道和非弹道两种
模型,并且,我们把两种模型做了比较。
最后是本文工作重点,我们利用非弹道模型较好地拟合了 BL Lac 天体 0735+178
喷流轨迹的变化,并在非弹道模型的基础上预测了今后喷流轨迹的变化,这些都需
要进一步的观测来检验。

关键词:活动星系核(AGN) BL Lac天体喷流进动视超光速运动
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华中科技大学硕士学位论文
Abstract
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
90ο 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
and .. 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 pton scatter subsequently.
Secondly, the jet precession and the apparent superluminal motion of jet in the active
galactic nuclei(AGN) 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 n