其他摘要 | For the reason of violent activities and extremely physical conditions, numerous astronomers and astrophysicists are attracted to conduct the researches on active galactic nuclei (AGNs). The studies certainly will improve our understanding of the cosmological evolution, the growth of black hole, the production and evolution of galaxies. This will also expands our knowledge on the physical processes with extreme conditions, for example, the process of energy transformation with strong gravity. The jet in AGN even has its inconceivable but charmed properties: a huge energy carrier moving with relativistic velocity and collimation to large distance. The studies on jet will unveil the physical processes around the black hole, the relationship between the central black hole and its host galaxy, and the most basic physics: the processes in magnetized plasma. In this thesis, we firstly introduce the general properties and the structure of AGN (Chapter 1). In the Chapter 2, we give the generally phenomenological properties of jet and the contents of the research on jet. The first part includes that, 1) the radiative transfer at the space from ANG to earth, 2) jet in different AGNs, 3) the spectra energy distribution (SED) of jet emission, 4) the variability of jet emission, 5) the space structure of jet, 6) the polarization, 7) the relativistic effect on jet emission, 8) the unified model. The second part includes the energy dissipation, the energy spread, and the production of jet. To discuss those aspects, we mainly focus on the point of radiation -- the bridge connecting the phenomenon and jet physics. Therefore, we discuss relative more detail on the radiative processes of jet emission in the Chapter 3. All above aspects are our summary, aiming at pointing out the present status and the problems in this field. Our research articles are listed in Chapters 4-6. The first one is that we give a method to determine which of external Compton (EC) or synchrotron self Compton (SSC) will dominate the $\gamma$-ray emission in Blazar. The results are, 1) that if the EC dominates the $\gamma$-ray emission, the luminosity and frequencies follow LIC/Lsy∝νIC/νsy2. 2) that if the SSC dominates the $\gamma$-ray emission, the size of the emission region has a low limit. We then use the method to test the Fermi bright AGNs, and find that most sources may have EC dominating the $\gamma$-ray emission. The second work is that we use the Fermi bright AGNs to test the blazar sequence. We find many blazars with low luminosity and low peak frequency, which is unexpected in phenomenological blazar sequence. While this contradictory can be explained within the "theoretical blazar sequence". Chapter 6 shows our study on non-radio loud AGN III Zw 2. We find that the jet in this source has similar jet power at that in $\gamma$-ray blazars. We also predict that the $\gamma$-ray emission from this source can be detected by Femri/LAT. While III Zw 2 is not included in the first catalog of Fermi/LAT AGNs. This may be the reason of that III Zw 2 is in its low state. We also argue that the studies on the jet in non-radio loud AGNs will improve our understanding on the growth and evolution of jet. The research on jet is now in its ascendant. This will be discussed in our last Chapter: Opportunities and Challenges! |
修改评论