太阳射电毫秒Spike辐射窄带宽的理论探讨

在磁拱底部非线性等离子体密度波传播期间,损失锥分布的反射电子驱动着电子迴旋maser不稳定性的增长,激励出二次谐频波模,支配着太阳射电毫秒Spike辐射。根据这个理论模型,本文着重研究了太阳射电毫秒Spike辐射的频带宽度问题。对于典型参数,计算结果发现:辐射带宽一般为几MHz到几十MHz,最高为100MHz。而且通常折射出的二次谐频z模辐射带宽较窄,而二次谐频o模辐射带宽较宽。     

BLO0716＋71非热辐射的喷流模型：从射电到γ射线

本文探讨用相对论喷流模型解释ＢＬ Ｌａｃ天体０７１６＋７１从射电到γ射线的整修电磁波段的非热辐射。喷流的结构分两个区域描述：内区具有抛物线结构，喷流是加速的；外区具有圆锥形结构，喷流速度恒定。相对论电子的密度和最高能量，以及磁场等参数随距离向外按幂律下降。在此模型中，射电至紫外线起源于相对论电子的同步辐射，而高能的Ｘ射线和γ射线则起源于自康普顿散射。辐射的频率越高，产生区域越靠近中央能源机器。辐射     

Derivation of flare magnetic field and density from two simultaneous frequency observations

We developed a simple model for a flare loop, which was used to fit the emission in the microwave (17 GHz) and millimetre-wave (80 GHz) ranges for the giant flare of 1991 June 4. The simplicity of the model enabled the exploration of a wide range of parameters in a reasonable time. It was possible, using the simple model, to derive from the 17- and 80-GHz data the magnetic field and the number density for every measurement point in the time range we chose to fit.     

Gas motions in the plane of the spiral galaxy NGC 3631

The velocity field of the nearly face-on galaxy NGC 3631, derived from observations in the H α line and H  i radio line, is analysed to study perturbations related to the spiral structure of the galaxy. We confirm our previous conclusion that the line-of-sight velocity field gives evidence of the wave nature of the observed two-armed spiral structure. Fourier analysis of the observed velocity field is used to determine the location of corotation of the spiral structure of this galaxy, and the radius of corotation R _c is found to be about 42 arcsec, or 3.2 kpc. The vector velocity field of the gas in the plane of the disc is restored, and, taking into account that we previously investigated vertical motions, we now have a full three-dimensional gaseous velocity field of the galaxy. We show clear evidence of the existence of two anticyclonic and four cyclonic vortices near corotation in a frame of reference rotating with the spiral pattern. The centres of the anticyclones lie between the observed spiral arms. The cyclones lie close to the observed spirals, but their centres are shifted from the maxima in brightness.     

密云232MHz星表的可靠性研究(英文)

利用密云综合孔径射电望远镜，在232MHZ频率，对于北纬30°以上天区的巡天已经完成.除了银道面区域（|b|＜10°）的射电源外，密云总星表（MGC）共包含了26957颗射电源．MGC的完整性和均匀性已在另文讨论．本文将利用所有处理完的MSRT资料和其它已发表的主要射电源表，研究密云总星表的可靠性．     

太阳射电快速事件的初析

本文着重介绍了紫金山天文台在１０cm波段上观测到的太阳射电快速结构事件资料，并对其进行了初步的分析.得到的一些结果如下:１．快速事件的宽度介于几十毫秒一几百毫秒的变化范围内；每秒出现的频数介于２１－１之间；２．从ｓｐｉｋｅｓ事件的形态上，也有着不同的结构特征；有的ｓｐｉｋｅ结构比较简单，基本上是一个个的单脉冲，而有的则比较复杂，即在每个ｓｐｉｋｅ尖峰上，还叠加有亚－精细结构。