II Status Reports of Research Activities 1. Subaru Telescope 1. Subaru Telescope Staff to be synthesized in many ways and at various places such as the Big-Bang, the inter-stellar medium, or in stars like novae and As of the end of FY 2014, the Subaru Telescope Project supernovae. Thus Lithium provides us key information about staff consisted of 19 dedicated faculty members including six the origin and evolution of matter in the Universe. This was the stationed at Mitaka, six engineers, and three administrative first direct detection of a site where Lithium was synthesized staff members. Additional staff members include five research and ejected. This confirmed that nova explosions are indeed the experts, one postdoctoral fellow, and seven administration major supplier of the Lithium seen in the present-day Universe. associates, all of whom are stationed at Mitaka. Moreover, 11 research/teaching staff members, 10 of whom are stationed at (4) High spatial resolution imaging of one of Jupiter’s Galilean Mitaka, and two engineers at Mitaka are posted concurrently. satellites with NIR camera IRCS assisted by adaptive optics The project also has 83 local staff members dispatched from unveiled the fact that the satellite is illuminated, though only the Research Corporation of the University of Hawaii (RCUH), at low level (1/100 of the normal brightness), even when it’s including scientific assistants; engineers in charge of software eclipsed by Jupiter. This indicates that sun light refracted by the and observational instruments; technicians for facilities, matter in the atmosphere above Jupiter’s surface illuminates the machinery, vehicles, and laboratories; telescope/instrument Galilean satellite in Jupiter’s shadow. operators; secretaries; librarians; administrative staff; researchers employed for Grant-in-Aid for Scientific Research; and graduate 3. Open Use students. These staff members work together in operating the telescope, observational instruments, and observational facilities; The Subaru call for open use proposals is issued every six and in conducting open-use observations, R&D, public outreach, months. The periods are from February 1 to July 31 (S14A) and and educational activities. from August 1 to January 31 (S14B). The Mitaka office of the Subaru Telescope at the National Astronomical Observatory 2. Science Highlights of Japan (NAOJ) campus accepts the submitted proposals. The Subaru Time Allocation Committee, established under the In the FY 2014, Subaru Telescope produced many outstanding NAOJ advisory committee for optical and infrared astronomy, scientific outcomes which were published in major international selects the proposals to accept, based on the evaluations and journals. Below are some examples: comments of the referees. In S14A, 70 programs (104 nights) were accepted out of 163 submitted proposals, requesting 403.6 (1) Deep high-z imaging observation with Suprime-Cam, the nights in total. In S14B, 58 proposals (103 nights) were accepted optical wide-field camera, discovered seven Ly-alpha emitters out of 133 submitted proposals, requesting 366.7 nights in total. at z ~ 7. The very low number density of such high-z galaxies In S14A and S14B respectively, there were 11 and 3 accepted (only 1/5 of that at z < 6.6) strongly suggests that the neutral open use proposals by foreign principal investigators, excluding gas fraction (H I) in the Universe increases rather abruptly from University of Hawai`i observing time. The number of applicants z = 6.6 towards z ~ 7, which thus prevents Ly-alpha photons from involved in the submitted proposals was 1806 for Japanese escaping and reaching us. This result has a strong impact on the researchers (Japanese astronomers at any institute and non- study of re-ionization in the early Universe. Japanese astronomers belonging to Japanese institutes) and 642 for foreign researchers. The number of researchers in accepted (2) High resolution optical spectroscopy with HDS of a very proposals was 891 for Japanese astronomers and 260 for foreign metal poor star in the Milky Way Galaxy revealed an abnormal astronomers. abundance pattern of chemical elements, characterized by low In S14A and S14B, the number of open use visiting abundances of Carbon, Magnesium and Cobalt. This pattern observers was 422, of which 60 were foreign astronomers. can only be reproduced by a model of the supernova explosion 34 astronomers observed remotely from Mitaka. The Mitaka of a super massive star (1000 times more massive than the office of the Subaru Telescope takes care of proposal handling Sun). Such a high mass for the first generation of stars had and evaluation, travel procedures and travel support for the been theoretically favored and proposed, but this was the first observers. The Hawai`i office makes the observing schedule observational evidence to support this scenario. and supports the accommodations and transportation for visiting observers in Hawai`i. In S14A and S14B, 94.8 % of the open use (3) High resolution optical spectroscopy with HDS of a nova, time (including University of Hawai`i time) was used for actual which was discovered in Aug 2013, revealed that a large amount astronomical observations, after excluding the weather factor of Lithium has been synthesized in this nova. Lithium is thought and downtime due to primary mirror coating. About 3.4 %, 0.2 %, 070 II Status Reports of Research Activities and 1.6 % of observing time was lost due to instrument trouble, (Suprime-Cam), Faint Object Camera And Spectrograph communication trouble, and telescope trouble, respectively. (FOCAS), High Dispersion Spectrograph (HDS), Infrared In S14A and S14B, remote observations from Hilo were not Camera and Spectrograph (IRCS), Cooled Mid-infrared Camera conducted. However, remote observations from Mitaka, where and Spectrograph (COMICS), Multi-Object Infrared Camera observers in Mitaka could participate in observations remotely, and Spectrograph (MOIRCS), Fiber Multi-Object Spectrograph in addition to on-site observers at the summit, were conducted (FMOS), and 188-elements Adaptive Optics and Laser Guide with limited function as a trial, for 8 programs with 30 nights. Star system (AO188/LGS). Service observations were made for 7 nights. To make Since the beginning of open-use observations in FY 2013, the best use of the limited resources at observatories on top of the software and hardware of HSC have been continuously Maunakea, Subaru Telescope has been exchanging telescope improved. As a result, the operation of the filter exchange time with Keck and Gemini. The number of time exchange system, shutter, and auto-guider system have been stabilized nights between Subaru Telescope and W. M. Keck Observatory significantly. Discussions on how to handover the operation was 5 in S14A and 3 in S14B. That between Subaru Telescope and maintenance of HSC from the development team to the and Gemini was 6 in S14A and 5 in S14B. observatory are underway. There are several upgrade projects for the other facility 4. Telescope Maintenance and Performance instruments: a MOS unit for HDS, an upgrade of the MOIRCS Improvement detectors, and implementation of polarimetric functions to IRCS and COMICS. For the HDS MOS unit, the supporting The general performance of the Subaru Telescope continues structure was transported to Hawai`i and study of its mechanical to be maintained the same as in the previous year. This year, interface to the telescope has been started. The fabrication of both the optical tertiary mirror and infra-red tertiary mirrors optical components such as fibers is still ongoing in Japan. For were recoated. During the recoating work, the mechanical drive the MOIRCS detectors, we have succeeded in operating the of the tertiary mirrors was re-adjusted to improve reliability. arrays and started characterization and parameter optimization. Day crews took over the installation and removal work of both The IRCS polarization function has been tested on sky and, after Hyper Suprime-Cam (HSC) and its filter exchange unit (FEU). characterizing the polarimetric performance and examining the As troubleshooting, the mirror cover open/close sensors, main calibration strategy, it was decided to open the polarimetry mode shutter open/close sensors, and shutters of the Shack-Hartmann starting from S15B. sensor were replaced. The rubber springs of the dome bogie In parallel to those upgrade projects, discussions on how have been replaced. Some new functions were added to the Top we maintain or stop operations of the facility instruments Unit Exchanger (TUE) for secure operation. The dome barcode are underway. To establish the plan for Subaru Telescopes’s system has also been upgraded. We also strived to conduct instrumentation, we summarized information such as preventive maintenance. competitiveness, demand, publications, and work load for In addition, while promoting improvements in the maintenance/troubleshooting of the facility instruments. performance and operational efficiency of the Subaru Telescope, Based on the results, an instrument plan was proposed to the renovation proceeded for the telescope control units which community in the User’s Meeting. Discussions and planning of have been in place for more than 10 years since installation. Subaru Telescope’s instrumentation including decommission of The following local control units were renovated or modified in facility instruments are still ongoing. this year: cover control unit (CVCU), field rotator control unit In FY 2014, two carry-in (PI-type)