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The foundation of millimeter wave VLBI station at Kagoshima

鹿儿岛毫米波VLBI站奠基

基本信息

批准号：
04452014
负责人：
OMODAKA Toshihiro
金额：
$ 4.48万
依托单位：
Kagoshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1994
项目状态：
已结题

项目摘要

Radio astronomers have developted methods for combining signals from radio telescopes scattered around the globe, creationg an effective aperture thousands km across. This technique, known as very long base line interferometer (VLBI), has elevated astronomical angular resolution measurements to new heights. In Japan, two mm VLBI telescopes have been performing. One in 45 m telescope at Nobeyama (NRO), and the otheris 34 m telescope at Kashima (CRL). Recently, a new mm VLBI telescope was constructed at Mizusawa (Mizusawa Astrogeodynamics Observatory). However, these telescopes are situated in the northern part of Japan. Our project is to construct a new mm VLBI station in the southern part of Japan, creating an effective aperture with the size of Japanese Islands. The 6m telescope was moved from Nobeyama Radio Observatory to Kagoshima. We finished the construction of the antenna and installed a 22 GHz cooled receiver in 1992. Owing to the smallness of this antenna, mm-VLBI observations … More require substantial technical efforts : The system has two distinctive characteristics as compared with current VLBI practice in order to improve thesensitivity. One is the capability of a burst mode operation with a high speed sampller and a large capacity memory. The other is a new bandwidth synthesizer mode operation using both high speed sampler and filters instead of video converters. Optical fiber cables are used for transmission of wide IF band (2GHz) for these new methods.First Kagoshima-Nobeyama-Mizusawa interferometer VLBI experiment was done in 1993 with collaboration from the Nobeyama Radio Observatory, and Mizusawa Observatory. The longest baseline of this network is 1300 km which provides a fringe separation of 2 milliarcsecont at 22 GHz.Recently, we started the monitor VLBI observations of H_2O maser sources in order to detect the apparent motions of masers in months. These data will provide irreplaceable insights into the inner working of interstellar clouds.Also, we are now pushing a plan of 43 GHz VLBI observations and will install a 43 GHz cold receiver in 1995. Less

射电天文学家已经发展出一种方法，可以把分散在地球仪上的射电望远镜的信号组合起来，形成一个直径数千公里的有效孔径。这种被称为甚长基线干涉仪（VLBI）的技术将天文学的角分辨率测量提高到了新的高度。在日本，两个毫米VLBI望远镜一直在工作。一个是位于野边山的45米望远镜，另一个是位于鹿岛的34米望远镜。最近，在水泽天文地球动力学观测站（Mizusawa Astrogeodynamics Observatory）建造了一台新的毫米VLBI望远镜。然而，这些望远镜位于日本的北方。我们的项目是在日本南部建造一个新的毫米VLBI站，创建一个日本岛屿大小的有效孔径。6米望远镜从野边山射电天文台搬到鹿儿岛。我们完成了天线的建设，并在1992年安装了一个22 GHz的冷却接收机。由于该天线体积小，毫米VLBI观测 ...更多信息需要大量的技术努力：与现行VLBI实践相比，该系统具有两个显著的特点，以提高灵敏度。一个是具有高速采样器和大容量存储器的突发模式操作的能力。另一种是使用高速采样器和滤波器代替视频转换器的新带宽合成器模式操作。1993年，在野边山射电天文台和水泽天文台的合作下，鹿儿岛-野边山-水泽干涉仪VLBI实验首次完成。该观测网的最长基线为1300 km，在22 GHz处的条纹间隔为2毫弧秒。最近，我们开始了对H_2O脉泽源的VLBI监视观测，以探测脉泽的视运动。这些数据将对星际云的内部工作提供不可替代的见解。此外，我们正在推动一项43 GHz VLBI观测计划，并将于1995年安装一台43 GHz冷接收机。少