Abstract

We have developed a system of simultaneous observations in the 22 and 43 GHz bands using the Nobeyama 45 m telescope, and are also working to add the 86 GHz band. Multi-frequency observations are realized by mounting perforated plates in the optics as dichroic frequency-selective devices. This paper presents the development of the perforated plate for the 22 and 43 GHz bands and the results of the commissioning observations with this plate on the Nobeyama 45 m telescope. The perforated plate is designed to be installed in the large telescope optics with a physical beam diameter as large as $50\:$cm for transmitting the higher frequency (43 GHz) band and for reflecting the lower frequency (22 GHz) band. The developed plate achieves an insertion loss of $0.22\:$dB (5%) at $43\:$GHz. The effects of the mounted plate on the systematic offsets and on the accuracy degradation of pointing were confirmed to be negligible. The differences in the main-beam/aperture efficiencies from those without the plate were confirmed to be within a few percent points. In addition, we successfully detected interferometry fringes in a very long baseline interferometry (VLBI) observation using the 45 m telescope and the VLBI Exploration of Radio Astrometry (VERA) 20 m telescopes, which confirmed that the dual-band observation system is operationally effective in both single-dish and VLBI observations.

中文翻译：

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Nobeyama 45 m望远镜的22/43 GHz波段准光学带孔板和双波段观测系统的开发

摘要

我们开发了使用Nobeyama 45 m望远镜在22 GHz和43 GHz波段进行同步观测的系统，并且正在努力增加86 GHz波段。通过将穿孔板安装在光学器件中作为二向色频率选择装置，可以实现多频观测。本文介绍了针对22 GHz和43 GHz频段的多孔板的发展以及在Nobeyama 45 m望远镜上对该板的调试观测结果。穿孔板设计用于安装在大型望远镜光学元件中，其物理光束直径高达$ 50 \：$ cm，用于发射较高频率（43 GHz）频带并反射较低频率（22 GHz）频带。在$ 43 \：$ GHz时，已开发的板实现了$ 0.22 \：$ dB（5％）的插入损耗。可以确定安装的板对系统偏移和指向精度的影响可以忽略不计。与没有平板的主光束/光圈效率的差异被确认在几个百分点之内。此外，我们使用45 m望远镜和VLBI射电占星术（VERA）20 m望远镜在很长的基线干涉仪（VLBI）观测中成功检测到干涉仪条纹，这证实了双波段观测系统在操作上有效单盘观测和VLBI观测。