致密射电源的快速偏振变化和星际闪烁模型

Rapid Polarization Variations of Compact Radio Sources and interstellar Scintillation Models

以类星体０９１７＋６２４中１９８９年５月观测到的ＩＤＶ事件为实例，尝试提出一个４成分模型（１个稳定成分和 ３个闪烁成分）以充分解释在 ６ ｃｍ波长上观测到的偏振变化，包括流量和偏振流量的相关性和反相关性以及它们之间的快速转化．对于 ２０ ｃｍ波长上观测到的偏振变化，３成分模型（１个稳定成分和３个闪烁成分）已足以解释全部现象．文中提出的闪烁模型在解释ＩＤＶ事件的偏振变化方面改进了以前的模型拟合．

A discussion on interstellar scintillation models for rapid polarization variations of compact extragalactic radio sources is presented in the paper. Taking the IDV event observed in May 1989 in QSO 0917+624 as an example, we propose that a 4-component model with one steady and three scintillating components is needed to fully explain the observed polarization variations at 6 cm, including the correlation and anti-correlation between the flux density and polarized flux density, and the rapid transition between them. For the polarization variations observed at 20cm, a 3-component model (one steady plus two scintillating components) is sufficient. The scintillation model proposed here for intraday polarization variations improves the previous model-fitting.