利用Effelsberg和乌鲁木齐Radio Telescopes观测IntraDay变源
Observations of IntraDay Variable sources with the Effelsberg and Urumqi Radio Telescopes
摘要：
利用乌鲁木齐25米望远镜和Effelsberg 100米望远镜对经典日内变星（IDV）和IDV候选源进行了观测。该项目的目的是研究日内变率的起源，这是一种在大约30%的平谱射电类星体中观察到的现象。Effelsberg-Urumqi的同步观测表明，乌鲁木齐天线虽然直径相对较小，但非常适合IDV实验。然而，少数乌鲁木齐的数据集，原来是一个虚假的$\sim 24$小时调制的影响，这种影响已被删除的数据减少的一种新的程序。在大约14个月的时间里，收集了12个观测时期，总观测时间超过45天。历元在全年中有规律地分布，以检查在变率时间尺度中是否存在系统性的年度变化-这是验证变率的源外部模型的一致性的关键测试。对监测源的初步时间分析揭示了S5~0716+714特征时间尺度减慢的一些线索，如果得到证实，这一结果与先前IDV研究相反，将与变异性的源外部起源相容。对于S4~0954+658，未检测到时间尺度的显著调制。
英文摘要：
A sample of classical IntraDay Variable (IDV) and IDV candidate sources has been monitored with the Urumqi 25m telescope and the Effelsberg 100m telescope. Aim of the project is to investigate the origin of IntraDay Variability, a phenomenon which has been observed in about 30% of flat spectrum radio quasars. Simultaneous Effelsberg-Urumqi observations demonstrated that the Urumqi antenna, although relatively small in diameter, is well suitable for IDV experiments. A few Urumqi datasets, however, turned out to be affected by a spurious $\sim 24$ hours modulation, an effect which has been removed by means of a new procedure for data reduction. In about 14 months, 12 epochs of observation have been collected, for a total observing time of more than 45 days. The epochs are regularly distributed over the whole year, in order to check for the presence of systematic annual changes in the variability time scales - a crucial test for verifying the consistency of source-extrinsic models of the variability. Preliminary time-analysis of the monitored sources revealed some hint for a slowing down of the characteristic time scales of S5~0716+714, a result that, if confirmed, would be compatible with a source-extrinsic origin of the variability, in contrast to previous IDV studies. No significant modulation of the time scales has been detected for S4~0954+658.
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