视超光速运动与加速模型

用相对论加速喷流模型对４８个具有视超光速的射电源进行了分析，结果不但支持流行的喷流模型而且说明加速模型是合理的。     

视超光速运动的相对论超光速模型

从相对论出发，在视超光速源质心相对于观测者静止的条件下，推导出两个向相反方向运动的视超光速子源之间的视速度方程，这一方程包含了相对论射束模型的表现横向速度公式，且对高、低速不同条件均为适用。     

视超光速运动的相对论超光速模型

从相对论出发，在视超光速源质心相对于观测静止的条件下，推导出两个向相反方向运动的视超光速子源之间的视速度方程，这一方程包含了相对论射束模型的表观横向速度公式，且对高，低速不同条件均为适用。     

视超光速运动的一个统计检验

本文利用文川提供的视超光速运动数据，对标准宇宙模型、相对论束模型及同步加速自康普顿散射机制在视超光速运动计算方面是否相容的问题进行统计检验．结果表明，理论预言与实际数据相吻合，上述诸理论是相容的，并且它们对视超光速运动的综合解释是合理的．     

射电源0420—014,1334—127和2345—167中的视超光速运动

本文叙述南天区５ＧＨｚＶＬＢＩ普查中新发现的视超光速射电源，０４２０－０１４，１３３４－１２７和２３４５－１６７，这些结果尚待进一步的观测加以证实。     

射电源0420—014,1334—127和2345—167中的视超光速运动

本文叙述南天区 5GHzVLBI普查中新发现的视超光速射电源 ,0 4 2 0— 0 1 4,1 334—1 2 7和 2 345— 1 67,这些结果尚待进一步的观测加以证实     

视超光速源0106 013的观测研究

我们在利用上海和ＳＨＥＶＥ组成的ＶＬＢＩ网做南天区５ＧＨｚＶＬＢＩ普查的过程中，对致密射电源０１０６＋０１３的视超光速运动作了进一步的研究．结果表明：（１）分量１最有可能是核；（２）原视超光速喷流分量仍以０．２ｍａｓ／ｙｒ的自行速度向外运动；（３）发现一个新分量的爆发，新分量也是视超光速的，自行速度为０．１８ｍａｓ／ｙｒ；（４）喷流在大约５ｍａｓ处有较明显的弯曲，然后趋于与ＶＬＡ喷流的方向一致．     

视超光速源的统计分析

本文收集了视超光速源样本的有关观测数据，在同步加速自康普顿散射机制下导出了各源的多普勒因子，再利用视超光速源的相对论射束模型计算样本源的有关物理量，如射电光度和亮温度，并与它们的观测值作直接的比较，得到较好的相关结果。这些结果支持了活动星系核中具有相对论射束运动的假设。同时我们比较了样本源的射电、光学、Ｘ射线的发现它们之间有一定的相关性，说明在不同波段上的辐射机制可能存在某种联系。     

视超光速运动在3C390.3中的再证认

本文讨论了河外射电源3C390.3的VLBI监测和它的喷流中的视超光速运动。     

Superluminal Motion and Polarization in Blazars

A relativistic beaming model has been successfully used to explain the observed properties of active galactic nuclei (AGNs). In this model there are two emission components, a boosted one and an unbeamed one, shown up in the radio band as the core and lobe components. The luminosity ratio of the core to the lobe is denned as the core-dominance parameter (R = LCore/LLobe). The de-beamed radio luminosity (Ldbjet) in the jet is assumed to be proportional to the unbeamedluminosity (Lub) in the co-moving frame, i.e., f = Ldbjet/Lub, and f is determined in ourprevious paper. We further discuss the relationship between BL Lacertae objects (BLs) and flat spectrum radio quasars (FSRQs), which are subclasses of blazars with different degrees of polarization, using the calculated values of the ratio f for a sample of superluminal blazars. We found 1) that the BLs show smaller averaged Doppler factors and Lorentz factors, larger viewing angles and higher core-dominance parameters than do the FSRQs, and 2) that in th     

视超光速射电节点的频谱演化:持续供能的喷流—激波模型

本文提出一个持续供能的喷流—激波模型来解释视超光速射电节点频谱演化的普遍特性．理论计算指出，射电爆发频谱的反转频率νm和频谱极大流量Sm之间的关系具有典型的3阶段演化方式，并且与类星体3C345中观测到的视超光速节点C4的演化行为相当好地符合．令Sm∝ν，则在上升阶段ζ≤3；在平坦变化阶段ζ≈0，而在衰减阶段ζ≈1．爆发幅度和流量极大的迟后时间对频率的关系△Smax（ν）和△t（ν），都具有Blazar天体中观测到的射电爆发的普遍形式．本文提出的激波模型，考虑到驱动气体的持续注入和激波后等离子体的绝热膨胀．因此提供了对相对论喷流中激波形成和演化的物理原因更深入的理解．并对Blazar天体中视超光速节点频谱演化提出了新的解释．     

3C345中视超光速节点运动轨道的数学描述

本文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,又可以描述外部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（例如ＰＫＳ０５２８＋１３４）中视超光速节点的运动是有用的。并有助于研究节点流量的内禀变化。     

Faster-than-light motion in quasars

Over the past fifteen years, observations of some quasars with the techniques of very-long-baseline interferometry have shown that the angular separation between pairs of radio-emitting regions in their cores is increasing year after year. If the quasars are indeed as far away as implied by Hubble’s law, then these angular motions translate into linear speeds several times the speed of light. Several theoretical scenarios have been proposed to show that the observed motions are illusory. The leading contender in this field — the relativistic beam model — and an alternative offered by the concept of a gravitational screen are described and compared in the light of recent observational data.     

Superluminal Kinematics in the Milne Universe: Causality in the Cosmic Time Order

The causality of superluminal signal transfer in the galaxy background is scrutinized. The cosmic time of the comoving galaxy frame determines a distinguished time order for events connected by superluminal signals. Every observer can relate his rest frame to the galaxy frame, and compare so the time order of events in his proper time to the cosmic time order. In this way all observers arrive at identical conclusions on the causality of events connected by superluminal signals. The energy of tachyons (superluminal particles) is defined in the comoving galaxy frame analogous to the energy of subluminal particles. It is positive in the galaxy frame and bounded from below in the rest frames of geodesically moving observers, so that particle-tachyon interactions can be based on energy-momentum conservation. We study tachyons in a Robertson-Walker cosmology with linear expansion factor and open, negatively curved 3-space (Milne universe). This cosmology admits globally geodesic rest frames for uniformly moving observers, synchronized by Lorentz boosts. In this context we show that no signals can be sent into the past of observers. If an observer emits a tachyonic signal, then the response of a second observer can never reach him prior to the emission, i.e., no predetermination can occur. The proof is based on the positivity of tachyonic energy. This revised version was published online in July 2006 with corrections to the Cover Date.     

活动星系核统一模式的统计检验

本文对视超光速源样本的有关数据进行统计分析，检验活动星系核统一模式。给出各类视超光速源的Ｒ（核光度与扩展区光度之比）分布和喷流与视线的平均夹角　。分析源样本的Ｒ、洛伦兹因子ｒ、喷流的投影尺度ｄ和线性尺度ｌ间的关系，发现Ｒ和ｄ之间存在反相关、ｒ和ｌ之间存在相关的特性，这些结果有利于说明活动星系核统一模式的取向效应。     

An Analytic Model of Three-Body Mean Motion Resonances

It has been recently shown that the resonances among the mean motions of an asteroid, Jupiter and Saturn are very important for the origin of chaos in the asteroid belt. We develop an analytic model for these three-body resonances which allows quantitative predictions on their amplitude and libration timescale. We also discuss why these resonances are chaotic. This revised version was published online in July 2006 with corrections to the Cover Date.     

质心运动的视超光速源的运动规律

在源的质心固定的视超光速模型的基础上，进一步出在质心运动情况下的视超光速运动的视速度议程，在喷流方向与源的退行方面相反的情况下，推导核与子源速率相等及核固定条件下子源真实速度的方程，然后代入视速度和由自康顿效应推算的喷流与视线的夹角数据，从而求出上述极值条件下子源的真实速度，再与对应源的哈勃红移速度相对照，结果发现，源的运动对其子源的速度没有影响。     

Is the VLBI core of 3C 345 moving?

In the superluminal source quasar 3C 345, five VLBI knots have been observed to have superluminal motion and, in particular, the two knots C₄ and C₅ move along different curved orbits. This paper examines the possibility that this pair of orbits are due to the motion of the radio core. Using the available data, the motions of C₄ and C₅ are resolved as a superposition of a motion of the core and a motion along a common orbit. The results show that such a resolution can fit well the observations. A brief discussion is made on further test of the model and its physical implications.