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射电噪活动星系核的多普勒因子的研究
【作者】 吴玉中；
【导师】 马力；
【作者基本信息】 云南师范大学 ， 天体物理， 2008， 硕士
【摘要】 活动星系核(AGNs:Active Galactic nuclei)是近年来天体物理学中非常活跃的研究领域,涉及天体物理学的最基本的问题,活动星系核的研究在能量产生,辐射机制等基本问题中占有重要的地位。Blazar天体是AGNs中具有极端物理性质的一个子类,它以大振幅快速光变、射电核主导、视超光速运动、非热辐射为主要特征。由于其特殊的性质,blazar天体提供了探测AGNs中心区域物理性质的可能。论文系统综述了活动星系核的特征、辐射机制和理论模型,并介绍了多普勒放大和聚束效应。收集了105个射电源样本,计算获得了射电源样本各子类的光学和X射线波段的多普勒因子,利用SPSS软件统计分析了不同子类的多普勒因子的分布,得到如下结果：1)BL Lac天体光学多普勒因子较小,但有较宽的分布范围；2)高偏振类星体的多普勒因子的中位值和平均值大于低偏振类星体；3)核占优类星体和瓣占优类星体的射电多普勒因子的中位值和平均值大于光学波段的多普勒因子,但BLLac天体和射电星系的光学多普勒因子大于射电波段多普勒因子。结果表明：具有较大的多普勒因子的源有很强的聚束效应。观测亮温度的平均值分布在很小的范围,所以观测亮温度和多普勒因子间存在明显的相关性。
【Abstract】 In recent years, active galactic nuclei are very hot researching-fields in astrophysics. They are related to the most fundamental problems in astrophysics. The research of Active galactic nuclei is very important in many fundamental problems, such as producing-energy, radiant mechanism. Blazar is one of the most extreme classes of active galactic nucleus, with high luminosity, large amplitude, radio core-dominance, apparent superluminal speeds and non-thermal process. Due to special character of blazars, we can know the physics properties of the region center of the AGNs.In this thesis, the properties, radiant mechanism and theory models of AGN were reviewed. Then we introduced the magnification and beaming effect of Doppler, we have collected 105 radio sources sample and calculated the Doppler factors in our sample at optical and X-ray bands, we obtained distributions of Doppler factors in our sample using SPSS software, our main works and results are as follow:1)BL Lacs has lower values and spanning a wider range in the Doppler factor at optical band; 2)The mean and median values of the Doppler factors is higher for HPQs than for LPQs; 3) The mean and median values of Doppler factors in CDQs and LDQs are larger for the radio band than for the optical band, However, these values of the Doppler factors at optical band for BL Lacs and radio galaxies are larger than the corresponding values at radio band. The distribution of the observed brightness temperature has a very small dispersion with a mean value. It shows that there is a significant correlation of the observed brightness temperature and Doppler factors.