LS 5039是一颗X射线双星，它有非热射电辐射。在$\sim 5$ GHz的辐射是相当稳定的和光学薄的，由一个主导的核心加上扩展的喷流状结构。有一个频谱营业额约1千兆赫，并在1年的时间尺度在234兆赫的变化的证据。我们使用现有的宽带无线电数据调查的无线电发射属性，并假设两种可能的情况来解释营业额：自由自由吸收的恒星风，或同步自吸收。我们利用转换频率、星风密度、辐射源的位置、大小、磁场和发射电子的洛伦兹因子之间的关系，以及对能量收支的合理假设，来推断低频射电辐射源的性质。此外，我们把这些信息的背景下，宽带无线电数据。低频射电辐射源的位置和大小可以限制在距主星$\ga$几个天文单位，其磁场为$\sim 3\times 10^{-3}-1$ G，电子洛伦兹因子为$\sim 10-100$。观察到的VLBA扩展结构的变化将指向电子体速度$\ga 3\times 10^8$ cm s $^{-1}$，而在5 GHz的变化少得多的辐射将指示VLBA核心$\la 10^8$ cm s $^{-1}$的速度。在高状态下，234 MHz的发射将主要来自比主导宽带无线电发射器更大的区域。我们提出了一个方案，其中次级对，通过伽马射线吸收和恒星风中移动，是后面的稳定的宽带无线电核心，而解决喷流一样的无线电发射将来自准直，更快，流出。
英文摘要：
LS 5039 is an X-ray binary that presents non-thermal radio emission. The radiation at $\sim 5$ GHz is quite steady and optically thin, consisting on a dominant core plus an extended jet-like structure. There is a spectral turnover around 1 GHz, and evidence of variability at timescales of 1 yr at 234 MHz. We investigate the radio emitter properties using the available broadband radio data, and assuming two possible scenarios to explain the turnover: free-free absorption in the stellar wind, or synchrotron self-absorption. We use the relationships between the turnover frequency, the stellar wind density, the emitter location, size and magnetic field, and the Lorentz factor of the emitting electrons, as well as a reasonable assumption on the energy budget, to infer the properties of the low-frequency radio emitter. Also, we put this information in context with the broadband radio data. The location and size of the low-frequency radio emitter can be restricted to $\ga$ few AU from the primary star, its magnetic field to $\sim 3\times 10^{-3}-1$ G, and the electron Lorentz factors to $\sim 10-100$. The observed variability of the extended structures seen with VLBA would point to electron bulk velocities $\ga 3\times 10^8$ cm s$^{-1}$, whereas much less variable radiation at 5 GHz would indicate velocities for the VLBA core $\la 10^8$ cm s$^{-1}$. The emission at 234 MHz in the high state would mostly come from a region larger than the dominant broadband radio emitter. We suggest a scenario in which secondary pairs, created via gamma-ray absorption and moving in the stellar wind, are behind the steady broadband radio core, whereas the resolved jet-like radio emission would come from a collimated, faster, outflow.
In this paper we present deep VLT multi wavelength imaging observations of the field around the radio galaxy PKS 1138-262 aimed at detecting and studying a (potential) proto-cluster centered at this radio source. PKS 1138-262 is a massive galaxy at z=2.16, located in a dense environment as indicated by optical, X-ray and radio observations. We had already found an over-density of Ly-alpha emitting galaxies in this field, consistent with a proto-cluster structure associated with the radio galaxy. In addition, we find 40 candidate H-alpha emitters that have nominal rest frame equivalent width > …
Proto-clusters associated with radio galaxies from z = 2 to z = 4
我们对射电星系的Lya发射线进行了窄带成像< 5. Subsequent spectroscopy has confirmed the identity of >，发现了6个z = 4.1的速度色散在300和1000 km/s之间的原星系团。在观测场中的发射线星系的数量是空白场中的4 ~ 15倍。这些结果有力地支持了高红移射电星系是位于星系团祖先中的中央最亮星系团的祖先的观点。
Radio emission of Shakhbazian Compact Galaxy Groups
在179个Shakhbazian致密星系群（ShCGs）区域内，观测到了来自NRAO VLA巡天（NVSS）（Condon et al.1998）和FIRST巡天（White et al.1997）的353个射电源。其中93个被确认为74个ShCG中的星系。六个射电源结构复杂。测定了22个源的射电频谱。ShCGs星系的射电光度普遍高于Hickson紧致群（HCGs）星系。对ShCG星系和HCG星系的射电（1.4 GHz）和远红外（60 $μ$ m）通量的比较表明，ShCG星系的射电辐射相对较强，而HCG星系的远红外辐射相对较强。分析了造成这种差异的原因。
