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。     

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。     

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。     

视超光速候选源0208—512和2243—123

本叙述南天区５ＧＨｚＶＬＢＩ普查的第二轮观测中所发现的视超光速候选源,０２０８－５１２和２２４３－１２３,这些结果尚待进一步的观测加以证实。     

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。     

河外射电源PKS2345—267视超光速运动的新证据

给出了利用上海、乌鲁木齐、意大利NOTO、南非HartRAO射电望远镜对河外射电源PKS2345－167的VLBI观测结果,并讨论其喷流中的子源的视超光速运动。     

视超光速候选源0208-512和2243-123

本文叙述南天区５ＧＨｚＶＬＢＩ普查的第二轮观测中所发现的视超光速候选源,０２０８－５１２和２２４３－１２３,这些结果尚待进一步的观测加以证实．     

太阳耀斑亮核和硬X射线环顶源运动的初步分析

分析了2个耀斑事件。这2个耀斑事件都具有双带结构，并伴有耀斑环顶部位置的硬X射线（HXR）辐射，这个辐射源我们称为环顶源。在文章中，通过求亮度重心的方法，我们对耀斑双带的相对运动，以及HXR环顶源的高度变化进行了分析。结果表明：耀斑相偶亮核间距离的时间曲线，与HXR亮度曲线具有相反的相关性，亮核间距离在HXR流量上升阶段会减少；与此同时，HXR环顶源的高度会下降。而通常的相偶亮核的分离运动以及环顶源的上升运动发生在极大相之后。     

Correlation between the Directions of the Magnetic Fields and Major Axes of Extragalactic Radio Sources

The distribution of relative position angles between the integrated intrinsic polarization (perpendicular to the direction of the intrinsic magnetic field) and the major axis of an extragalactic radio source were studied for different types of radio sources. Data for 280 extragalactic radio sources were used and it was found that there are large differences in the relative orientation of different types of radio sources. The directions of the intrinsic integrated magnetic fields correlate with the major radio axes of more elongated radio sources (K > 2.5, where K is the ratio of lengths of the major and minor axes of the radio images) and for radio sources of type FR II, whereas for less elongated objects (K < 2.5) and for radio sources of type FR I the magnetic fields do not correlate at all with the radio axes. An alternative mechanism for the formation of a radio galaxy from relativistic plasma ejected from the central part of an optical galaxy and moving in its large-scale, dipole magnetic field may be a theoretical basis for classification with respect to the elongation parameter K of the radio image.     

Study of the fast X-ray transient XTE J1901+014 based on INTEGRAL,RXTE, and ROSAT data

The source XTE J1901+014 discovered by the RXTE observatory during an intense outburst of hard radiation and classified as a fast X-ray transient is studied. The source’s spectral characteristics in the quiescent state have been investigated for the first time both in the soft X-ray energy range (3–20 keV) based on ROSAT and RXTE data and in the hard energy range (>20 keV) based on INTEGRAL data. A timing analysis of the source’s properties has revealed weak nonperiodic bursts of activity on time scales of several tens of seconds and two intense (～0.5–1 Crab) outbursts more than several hundred seconds in duration. Certain assumptions about the nature of the object under study are made.     

CENSORS: A Combined EIS–NVSS Survey Of Radio Sources – I. Sample definition, radio data and optical identifications

A new sample of radio sources, with the designated name CENSORS (A Combined EIS–NVSS Survey Of Radio Sources), has been defined by combining the National Radio Astronomy Observatory Very Large Array Sky Survey (NVSS) at 1.4 GHz with the ESO Imaging Survey (EIS) Patch D, a 3° by 2° region of sky centred at RA     , Dec. −21°00'00' (J2000). New radio observations of 199 NVSS radio sources with NVSS flux densities   S _{1.4 GHz} > 7.8 mJy  are presented, and are compared with the EIS I -band imaging observations which reach a depth of   I ∼ 23  ; optical identifications are obtained for over two-thirds of the ∼150 confirmed radio sources within the EIS field. The radio sources have a median linear size of 6 arcsec, consistent with the trend for lower flux density radio sources to be less extended. Other radio source properties, such as the lobe flux density ratios, are consistent with those of brighter radio source samples. From the optical information, 30–40 per cent of the sources are expected to lie at redshifts   z ≳ 1.5  .
One of the key goals of this survey is to accurately determine the high-redshift evolution of the radio luminosity function. These radio sources are at the ideal flux density level to achieve this goal; at redshifts   z ∼ 2  they have luminosities which are around the break of the luminosity function and so provide a much more accurate census of the radio source population at those redshifts than the existing studies of extreme, high radio power sources. Other survey goals include investigating the dual-population unification schemes for radio sources, studying the radio luminosity dependence of the evolution of radio source environments, and understanding the radio power dependence of the K – z relation for radio galaxies.     

PKS2250-41 and the Role of Jet Cloud Interactions in Powerful Radio Galaxies

We have studied the effects of the interaction between the radio jet and the ambient gas in the powerful radio galaxy PKS2250-41 (z = 0.31). Our results show that the gas has been accelerated, compressed, heated and collisionally ionized by the shock. This study helps us to understand the processes which determine the observed properties of many high redshift radio galaxies. This revised version was published online in July 2006 with corrections to the Cover Date.     

In situ oxygen,magnesium, and silicon isotopic compositions of the FUN inclusion Vigarano 1623-5

Oxygen, magnesium, and silicon isotopic abundances in Vigarano 1623-5 were studied using secondary ion mass spectrometry to investigate correlations between isotopic and petrologic properties of this unique forsterite-bearing FUN inclusion. Vigarano 1623-5 displays large, correlated mass-dependent fractionation effects, tightly linked to mineralogy within distinct petrologic units of the inclusion. The pyroxene-rich and melilite-rich interior parts of the inclusion display highly mass-fractionated isotopic compositions of oxygen, magnesium, and silicon, consistent with Rayleigh distillation during evaporation of a melt with initial oxygen composition close to a solar composition. However, the chemical composition, enriched in magnesium and silicon, suggests a precursor already fractionated by prior melt evaporation. A discontinuous igneous rim was produced by a flash-melting event followed by isotopic exchange in the rim melilite with planetary-like oxygen, mechanical fragmentation, and reassembly with an accretionary rim of heterogeneous materials. Al-rich minerals in 1623-5 show evidence for having crystallized with live ²⁶Al but at less than the “canonical” level of most CV calcium-aluminum-rich inclusions. However, well-defined ²⁶Al-²⁶Mg isochrons are not found and temporal implications are ambiguous.