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本介绍了一种用于射电天学谱指数研究的新方法－双色微分图解法，在进行谱指数分析所使用的多频图中，一般存在有不同的背景分量及大尺度缓变分量，使用本介绍的新方渚到的结果不受这两种成分的影响，这种新方法还可用于热及非热射电辐射分离，本还给出了应用实例，首次精确计算了ＳＮＲＧ７８．２＋２．１的多频空间谱指数分布。 相似文献
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张喜镇 《中国科学院上海天文台年刊》1995,(16):291-295
我们发展了两个图象处理方法以进一步改善图象质量和观测精度。这两种方法分别是双图高通滤波和短基线数据增补。 相似文献
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我们对北京天文台密云２３２ＭＨｚ星表和６Ｃ星表进行了系统的比较和研究，以期对密云星表的完备性和均匀性有一个定量的概念。 相似文献
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在１９９１－１９９３年期间,Ｃｏｍｐｔｏｎγ射线天台在射电源ＰＫＳ０５２８＋１３４中观测到两次很强的γ射线爆发,都伴随有毫米波射电大爆发。 相似文献
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High brightness temperatures are a characteristic feature of IntraDay Variability (IDV) of extragalactic radio sources. Recent studies of the polarization properties of some IDV sources (e.g., 1150 812, PKS 0405-385 and 0716 714) have shown that these sources harbor several compact IDV components with angular sizes of -10-30/uas and very high polarizations (of up to -50%-70%). These results indicate the possibility of the existence of uniform magnetic fields in the IDV components. We investigate the incoherent synchrotron and self- Compton radiation of an anisotropic distribution of relativistic electrons which spin around the magnetic field lines at small pitch angles. The brightness temperature limit caused by second-order Compton losses is discussed and compared to the brightness temperatures derived from energy equipartition arguments. It is found that anisotropic distributions of electrons moving in ordered magnetic fields can raise the equipartition and Compton brightness temperatures by a factor of up to -3-5. This would remove some of the difficulties in the interpretation of extremely high intrinsic brightness temperatures of > 1012 K (or apparent brightness temperatures of - 1014 K with a Doppler factor of -30). 相似文献
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Shan-Jie Qian S. Britzen A. Witzel T. P. Krichbaum Heng-Qian Gan Long Gao 《中国天文和天体物理学报》2014,(3):249-274
The kinematics of superluminal components in blazar 3C 454.3 are studied.Nine components are included： superluminal knots R1, R2, R3, R4, A, B, C and D（from Britzen et al. 2013） and C4 （from Pauliny-Toth 1998）. We find that their kine-matics derived from VLBI observations can be consistently interpreted in terms of ajet precession scenario with a period of about 14.5 yr. We discuss the model fits oftheir trajectory, distance from the core and apparent velocity. We show that the bulkLorentz factor （in the range 4 to 15） derived for these components does not have anydependence on the phase of the precession （or position angle for ejection）. The Lense-Thirring effect is assumed to interpret the precession of the jet nozzle. The resultsobtained for blazar 3C 454.3 are only suggestive. They are not unique and have yet tobe tested, but they might be useful for understanding the kinematics of superluminalcomponents in blazars and for disentangling different mechanisms and factors. 相似文献
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本提出一种数学方法来描述类星体３Ｃ３４５中视超光速节点的运动轨道,它既可以描述内部节点的螺旋运动,又可以描述外产节点的直线运动。这种统一的描述方法可能对描述其它致密射电源中视超光速节点的 有用的,并有助于研究流量的内聚变化 。 相似文献