Development of Optical Fiber-based Multi-Object Spectrograph for Investigations of Galaxy Formation History

点击翻译按钮获取中文摘要

We have developed a new near-infrared spectrograph capable of measuring spectra of high-redshift galaxies in the multi-object mode and/or in the 2-D mode, for the purpose of investigating systematic spectroscopic studies by survey observations of high-redshift galaxies and quasars. The specifications of the spectrograph are, the wavelength range of 0.8 to 1.8 microns, the multiplicity of 400 in the multi-object mode, and 250 in the 2-D mode (IFU mode). During the period of this developmental work from 2002 to 2004,we have designed and fabricated a prime-focus mechanical/optical unit, a near-infrared spectrograph with newly developed optical components, and a large array detector system. As of March 2004,we have been testing the fiber-slit images of the spectrograph as a whole, and the system will be tested on the Subaru Telescope in the first quarter of FY 2005,and then the spectroscopic observations will be made in the fall of 2005. Along with these developmental works, we have investigated high-redshift object such as normal galaxies, radio galaxies, and quasars, whose data were acquired by the unique near-infrared spectrograph (OHS) as well as the infrared imager (CISCO) at Subaru Telescope. Based on these spectroscopic and photometric data, we found chemical evolution of quasar environment by measuring near-infrared emission lines of metal elements such as Fe and Mg, and also found one or two massive galaxies at a high-redshift region with clear indication of disk feature. On the basis of the above results of developmental and observational works, we plan to continue systematic investigations of the galaxy/quasar evolution in the early universe by utilizing the unique capability of our high multiplicity instrument.