Versatile IF polarimeter at the IRAM 30m telescope
Versatile IF polarimeter at the IRAM 30m telescope
复制标题
IRAM 30m 望远镜上的多功能 IF 偏振计
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
M. Torres
中科院分区：
文献类型：
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作者：
C. Thum;H. Wiesemeyer;D. Morris;S. Navarro;M. Torres
我们报告了在IRAM 30米望远镜的中频（150兆赫）工作的偏振计的调试。通过适当的相移，偏振计增加了两个正交线极化外差接收器的振幅，并从这些信号中确定了所有四个Stokes参数。该偏振计允许连续体以及光谱线观测在所有毫米大气窗口可与30米望远镜。两个接收器之间的仪器相位，通过移相器控制，在3mm处不超过1度（rms）。仪器在轴视上的偏振光很小，Stokes U和v的偏振光小于1%。我们介绍了1999年开始的第一次大规模3毫米极化调查的结果。观测到大约100个通量密度大于0.8焦耳的活动星系核，其中许多是重复的。在几个时期的几个光源中发现了大于10%的线极化。我们简要地描述了两个光谱偏振调查的结果：SiO脉泽星和甲醇脉泽星。两极分化很容易在两组中发现。
We report on the commissioning of a polarimeter operating at the intermediate frequency (150 MHz) of the IRAM 30m telescope. The polarimeter adds, with suitable phase shifts, the amplitudes of two orthogonally linearly polarized heterodyne receivers, and determines from these signals all four Stokes parameters. The polarimeter allows continuum as well as spectral line observations in all millimeter atmospheric windows accessible with the 30m telescope. The instrumental phase between the two receivers, controlled through a phase shifter, does not exceed one degree (rms) at 3mm. Instrumental polarization on boresight is found to be small, below one percent for Stokes U and V. Limitations due to beam polarization are discussed. We present results from the first large scale 3mm polarization survey started in 1999. About 100 Active Galactic Nuclei with flux densities stronger than approximately 0.8 Jy were observed, many of them repeatedly. Linear polarization larger than 10 percent is found in several sources at several epochs. We briefly describe results from two spectro--polarimetric surveys: SiO maser stars and methanol masers. Polarization is easily detected in both groups.