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1.
于秦生 《天文学报》2001,42(2):148-154
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。  相似文献   

2.
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。  相似文献   

3.
视超光速运动的相对论超光速模型   总被引:3,自引:0,他引:3  
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。  相似文献   

4.
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.  相似文献   

5.
通过主要在短厘米波长的全球VLBI观测,已经现强射电类星体4C39.25在十秒差距尺度结构中的视超光速运动,其运动学图景表明该源是一个很特殊的视超光速源,近几年已提出了若干模型,试图解释这特殊的运动图景,报道不多的百秒差距尺度的VLBI观测,很可能有助于检验提出的模型,本文介绍用欧洲网及上海25m天线,在18cm波长对4C39.25所作的VLBI成象观测的初步结果,显示秒差距尺度复杂结构及可能存在  相似文献   

6.
通过主要在短厘米波长的全球VLBI观测,已经发现强射电类星体4C39.25在十秒差距尺度结构中的视超光速运动,其运动学图景表明该源是一个很特殊的视超光速源.近几年已提出了若干模型,试图解释这特殊的运动图景.报道不多的百秒差距尺度的VLBI观测,很可能有助于检验提出的模型.本文介绍用欧洲网及上海25m天线,在18cm波长对4C39.25所作的VLBI 成象观测的初步结果,显示百秒差距尺度复杂结构及可能存在的视超光速运动.  相似文献   

7.
类星体和活动星系核结构的变化及其中的视超光速运动,被认为是用VLBI方法所揭示的最重大的天体物理现象之一。十余年来积累了大量观测资料,迄今已经观测证实了不少于25个视超光速源,更广泛的监测和搜寻计划正在进行中。 本文从观测手段和结果两个方面,综述对视超光速源探测的方法及现状。在另一篇文章中将总结视超光速源的观测特征,以及为解释这些特征所作的有代表性而又较广为接受的理论探讨。  相似文献   

8.
艾小白 《天文学进展》2001,19(2):179-183
论述量子远程通讯的最新成就很可能意味着自然界存在超光速的信息联系,狭义相对论又面临新的考验,若考虑虚数“i”的作用,狭义相对论可与物质的超光速运动相容,而且不违反因果律,即使自然界存在超光速的物质运行也不可能动摇狭义相对论,建议设计实验测量德布罗意波的相速度并深入研究波粒二象性。  相似文献   

9.
视超光速源的统计分析   总被引:2,自引:0,他引:2  
洪晓瑜  蒋栋荣 《天文学报》1995,36(2):147-158
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。  相似文献   

10.
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.  相似文献   

11.
Based on the relativistic model of the apparent superluminal motion and under the condition that the center of mass of a superluminal radio source remains in motion relative to the observer, the equation of the apparent velocity between nucleus and component is derived. Assuming that the directions of jet and movement of superluminal radio source are opposite, then, supposing that the velocities of nucleus and components of SLS are equal and the nucleus is fixed, the equations of real velocity are respectively derived. With the data of Vapp and θ substituted in the equation of real velocity, the velocity of the components of SLS is obtained. Comparing the real velocity with the velocity of Hubble redshift of SLS, it is concluded that the movement of SLS has no influence on the velocity of components.  相似文献   

12.
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.  相似文献   

13.
Probability approach is considered in order to examine the plausibility of ballistic model explanation of superluminal phenomenon in extragalactic sources. It is shown that this approach is less probable for the explanation of observed data.  相似文献   

14.
1 INTRODUCTIONThe quasar 3C 273 (z = 0.158) is one of the classical rwho sources showal apparellt superltalnal motion (Zensus et al. 1990, 1997). It has a large-scale jet (~ 20n of length, 3C273A)elliltting at radio, optical and X-ray bands. It has been suggested that its compel source(3C 273B) is a rmm-blazar, Undergoing strong and rapid Variations in ratio, optical-UV, X-rayand 7-my bands at various tab scales (from hours to years, Courvoisier et al. 1998, Tet al. 1999, Stevens et …  相似文献   

15.
We have collected an up-to-date sample of 123 superluminal sources (84 quasars, 27 BL Lac objects and 12 galaxies) and calculated the apparent velocities (βapp) for 224 components in the sources with the A-CDM model. We checked the relationships between their proper motions, redshifts,βapp and 5 GHz flux densities. Our analysis shows that the radio emission is strongly boosted by the Doppler effect. The superluminal motion and the relativistic beaming boosting effect are, to some extent, the same in active galactic nuclei.  相似文献   

16.
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 kinematics derived from VLBI observations can be consistently interpreted in terms of a jet precession scenario with a period of about 14.5 yr.We discuss the model fits of their trajectory,distance from the core and apparent velocity.We show that the bulk Lorentz factor(in the range 4 to 15) derived for these components does not have any dependence on the phase of the precession(or position angle for ejection).The LenseThirring effect is assumed to interpret the precession of the jet nozzle.The results obtained for blazar 3C 454.3 are only suggestive.They are not unique and have yet to be tested,but they might be useful for understanding the kinematics of superluminal components in blazars and for disentangling different mechanisms and factors.  相似文献   

17.
What we observe as an apparent superluminal motion is the resultant velocity of Hubble flow and a local ejection. Taking Hubble flow into account, one can explain, problems posed for the relativistic beaming model, such as the one-sidedness problem and the untolerable extension of the depromected structure of some superluminal sources; the misalignment of small-and large-scale jets can be analyzed more appropriately. A significant by-product of the present investigation is the initiation to find a new way to determine the value of the Hubble constantH 0, provided that one can observe the superluminal motion at much longer wavelengths, say, meter wavelengths.  相似文献   

18.
Faster than light or superluminal motion was originally predicted as a relativistic illusion of ballistic moving ejecta, and confirmed in a few tens of sources observationally. However, the recent results of the long-term multi-epoch observations of quasars, active galaxies, tracing the structure further along the jets and following the motion of individual features for longer time, raise questions that are difficult to understand by the standard ballistic model. That is, the ejecta are aligned with the local jet direction, instead of the core; and within individual jets apparently inward-moving features are observed. Here, we show that these unexpected phenomena, although only a small fraction among large samples, indicate the existence of non-ballistic jet motion, in which a continuous jet produces a discrete hot spot. And the precession of such a hot spot in the plane of the sky appears superluminal. Therefore, a unified and simple interpretation to the new results is obtained, which can be further tested through its predictions on the evolution of ejecta. The study is of importance in the understanding of the nature of superluminal motion, the interaction of jets and surrounding materials, as well as the common physics underlying quasars and microquasars.  相似文献   

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