a New Method for Cross Polarized Delay Calibration of Radio Interferometers
a New Method for Cross Polarized Delay Calibration of Radio Interferometers
复制标题
射电干涉仪交叉极化时延校准的新方法
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
W. Cotton
中科院分区：
文献类型：
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作者：
W. Cotton
无线电干涉仪可以通过对每个天线处两个正交极化的所有组合进行互相关来测量传入波的完整极化状态。用于检测两个偏振态的独立电子设备组将在两个数据流之间引入差分仪器延迟。并行能见度组的单独校准的常用技术仍然允许两个并行系统之间的群延迟和相位的任意偏移。为了使用交叉偏振能见度，必须确定并消除该仪器偏移。本文描述了一种这样的技术并探讨了它在 Obit 包中的应用。该技术已成功应用于使用强偏振和弱偏振校准器的一些 EVLA 数据。
Radio interferometers can measure the full polarization state of incoming waves by cross-correlating all combinations of two orthogonal polarizations at each antenna. The independent sets of electronics used to detect the two polarization states will introduce a differential instrumental delay between the two data streams. The usual technique of separate calibration of the parallel-hand sets of visibilities still allows for an arbitrary offset in group delay and phase between the two parallel systems. In order to use the cross-polarized visibilities, this instrumental offset must be determined and removed. This paper describes one such technique and explores its application in the Obit package. The technique is successfully applied to some EVLA data using both strongly and weakly polarized calibrators.