STUDY OF STAR FORMATION HISTORY OF THE UNIVERSE BY MILLIMETER-WAVE BROAD BAND SPECTROSCOPY

这样做的目的。研究方向是研制毫米波宽带光谱仪“Z-Spec”，以确定亚毫米波星系的红移，这些星系被认为在宇宙早期处于形成阶段。Z-Spec的独特之处在于它的宽波长覆盖范围（λ=1.0 - 1.5mm），以便同时捕获来自碳单氧化物和电离碳原子的多条线，使我们能够测量亚毫米星系的可靠红移。这项研究是与美国宇航局/喷气推进实验室和加州理工学院合作进行的。利用这笔资金，我们开发了一个液氦低温恒温器，它容纳了宽带毫米波光谱仪，包括用于冷却探测器阵列的^3He + ADR冰箱。低温恒温器已经实现了在没有光谱仪热负荷的情况下保持冷冻剂超过96小时。低温恒温器在JPL运行良好，目前探测器和光谱仪的制冷系统已安装到低温恒温器中，正在进行性能评估。随后，NASA/JPL开发的探测器系统将被安装，然后Z-Spec的端到端评估将很快开始。2002年8月在夏威夷科纳举行的SPIE会议上报告了Z-Spec的发展现状。除此之外，我们还利用位于夏威夷莫纳克亚山的大型望远镜，如斯巴鲁和CFHT，对许多亚毫米星系进行了光学和近红外成像观测，这些星系是Z-Spec观测的候选星系。这些观测前的活动有助于了解亚毫米星系的性质。

The purpose of this.research is to develop a millimeter-wave broad-band spectrometer "Z-Spec", in order to determine the redshift of the submillimeter galaxies which are thought to be in their formation stages in the early universe. The uniqueness of the Z-Spec is its broad wavelength coverage (λ=1.0 - 1.5mm) in order to catch multiple lines from Carbon Mono-oxide and ionized Carbon atom simultaneously, enabling us to measure the reliable redshifts of the submillimeter galaxies. This research has been undertaken in collaboration with NASA/JPL and Caltech.Using-this grant, we have developed a liquid helium cryostat, which houses the broad-band millimeter wave spectrometer including its ^3He + ADR refrigerator for cooling the detector arrays. The cryostat has achieved to hold the cryogen over 96 hours without heat load from the spectrometer. The cryostat is working well at JPL and now the refrigerator system for the detectors and the spectrometer are installed in to the cryostat and under performance evaluation. Subsequently the detector system, developed at NASA/JPL, will be installed and then end-to-end evaluation of the Z-Spec will be soon started. Current status of the development of Z-Spec has been reported in the SPIE meeting at Kona, Hawaii, in August 2002.In addition to the above, we have also executed optical and near-infrared imaging observations for number of submillimeter galaxies which are candidates for the Z-Spec observations, with large telescopes such as Subaru as well as CFHT located in Mauna Kea, Hawaii. These pre-observation activities are useful to understand the nature of the submillimeter galaxies.