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The construction of 43GHz VLBI network and the project search for VLBI radio sources of phase-referencing VLBI astrometry with VERA.

43GHz VLBI网络建设及利用VERA寻找相位参考VLBI天体测量VLBI光源项目。

基本信息

批准号：
12440053
负责人：
OMODAKA Toshihiro
金额：
$ 8.13万
依托单位：
Kagoshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

VERA (VLBI Exploration of Radio Astrometry) is a new VLBI ax mainly aimed at study of the structure and dynamics of our Galaxy through high precision phase-referencing VLBI astrometry of astronomical maser sources. VERA, with its dual-beam antenna system, will enable us to observe a galactic maser and an extra-galactic reference source simultaneously in order to remove the atmospheric fluctuation. In order for VERA to achieve a 10μ as level accuracy, allowing us to obtain parallaxes of maser sources in the whole Galaxy, it is required that the maser and reference source must be located within 2°each other. This requires a large number of reference sources spreading over Galactic plane because H2O(22GHz) and SiO(43GHz) masers which are the main targets, are mostly concentrated in the galactic plane. Hence the search for VLBI sources in the galactic plane is indispensable to the success of VERA. In order to search for 43GHz VLBI sources, we started to install the 43GHz cooled receiver to 34m antenna which belongs to Kashima Space Research Center, Communications Research Laboratory in these Funds. By this we will start a 43GHz survey of continuum radio sources in the galactic plane using this 34m telescope and Nobeyama 45m telescope. We constructed small-sized cooled dewar and has succeeded in cooling the receiver. Further, we incorporated the Local oscillator (this Grant-IN-Aid) and installed these components in 34m telescope. The system noise temperature, including atmospheric loss, was 300K. In this test observations, very serious problems arosed. As the antenna inclined, the antenna pointing accuracy become significantly poor due to both the bending and hanging down of the subreflector. This knotty problems was mainly settled by Satoru Morisaki, a graduate student of Kagoshima University. He also set up high-resolution acousto-optical spectrometers.

VERA（VLBI Exploration of Radio Astrometry）是一种新的VLBI仪器，主要用于对天文脉泽源进行高精度的相位参考VLBI天体测量，研究银河系的结构和动力学。VERA的双波束天线系统将使我们能够同时观测银河脉泽和河外参考源，以消除大气波动。为了使VERA达到10μ s级的精度，使我们能够获得整个银河系的脉泽源的相位差，要求脉泽源和参考源的位置必须在2°以内。这就要求大量的参考源遍布银道面，因为作为主要目标的H_2O（22GHz）和SiO（43GHz）脉泽主要集中在银道面。因此，在银道面寻找VLBI源是VERA成功的关键。为了寻找43GHz VLBI源，我们开始在这些基金的通信研究实验室鹿岛空间研究中心的34米天线上安装43GHz冷却接收机。通过这一点，我们将开始一个43 GHz的调查连续无线电源在银道面使用这个34米望远镜和Nobeyama 45米望远镜。我们制作了小型冷却杜瓦，并成功地冷却了接收器。此外，我们还将本地振荡器（本补助金）安装在34米望远镜中。系统噪声温度（包括大气损耗）为300K。在这次试验观察中，出现了非常严重的问题。当天线倾斜时，由于副反射面的弯曲和垂下，天线指向精度变得明显变差。鹿儿岛大学的研究生森崎悟（Satoru Morisaki）主要解决了这个棘手的问题。他还建立了高分辨率的声光光谱仪。