类星体3C 286的一个早期VLBI观测结果

利用基于自校正和ＣＬＥＡＮ算法的现代ＶＬＢＩ混合成图技术，对Ｐｅａｒｓｏｎ等人于１９７６年观测得到的类星体 ３Ｃ ２８６在 １８ ｃｍ波段上的 ＶＬＢＩ数据重新作了处理．由此得到的图像要大大好于最初的处理结果，也获得了更多的有用信息．用几个Ｇａｕｓｓ模型去拟合校正后的ＵＶ数据，发现中央亮区可以被分解为两个致密结构，这与后来的高分辨率观测相一致．与不同历元的ＶＬＢＩ观测结果相比较，发现这两个致密结构间的距离不但在同一时间随观测频率变化，而且很有可能在同一观测频率上随时间变化．

An Early VLBI Observation of the Quasar 3C 286

Using the hybrid mapping technique based on self-calibration and CLEAN algorithms, we reprocessed the data of an early (1976) VLBI observation (by T. J. Pearson et al.) of quasar 3C 286 at 18cm, and obtained a high quality CLEAN map. We can get more information from the new map than from the old one. Four Gaussian models were used to fit the calibrated UV data. We found that the central bright region could be resolved into two compact components. This was in accordance with the later higher angular resolution VLBI observations. Comparing with the results of other VLBI observations, the distance between these two components was found to vary not only with frequency at a given time, but also with time at a fixed frequency.