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I Scientific Highlights April 2007–March 2008 Annual Report of the National Astronomical Observatory of Japan Fiscal 2007 TABLE OF CONTENTS Preface Shoken MIYAMA Director General National Astronomical Observatory of Japan I Scientific Highlights April 2007 – March 2008 001 II Publications, Presentations 1 Refereed Publications 044 2 Publications of the National Astronomical Observatory of Japan 056 3 Report of the National Astronomical Observatory of Japan 056 4 Conference Proceedings 057 5 Publications in English 064 6 Conference Presentations 065 Annual Report of the National Astronomical Observatory of Japan Fiscal 2007 PREFACE Shoken MIYAMA Director General of NAOJ I am pleased to present the Annual Report of the matter). National Astronomical Observatory of Japan (NAOJ) The dark matter and dark energy have not yet been for fiscal 2007. In the preface, I would like to focus on identified exactly but posed an enormous challenge to the activities and achievements related to one of the basic science (elementary particles theory and high- key topics of today’s astronomy as the status of NAOJ energy physics) with the findings obtained in the fields of activities are provided in each section of this report. astrophysics and astronomy (observational and theoretical Using numerous telescopes, NAOJ has been observing astronomy). A fundamental concept of astrophysics has astronomical phenomena in the universe including stars, been, so far, to grasp a reasonable picture of the universe planet systems, galaxies, clusters of galaxies, and cosmic based on basic science. However, it may be changed by large-scale structure (the entire structure of the universe). new emerging forces like the dark energy which can be a Recent studies have revealed that these astronomical trigger requiring a new approach to the science of the 21st materials which are visible with telescopes (starts and century. galaxies) account for only 4% of the total mass in the In the new phase of cosmology, NAOJ’s observational universe, indicating that most of the universe mass is instruments are playing a significant role, including made up of invisible materials named “dark matter” and VERA (VLBI Exploration of Radio Astrometry) of “dark energy”, 20% and 75% respectively. The presence Mizusawa VERA Observatory which has succeeded in of these invisible materials became known because of the determining the distance of the farthest star ever observed gravitational effects they have on visible objects. in our galaxy by the triangulation. This achievement The dark matter was suggested as a gravitational allowed NAOJ to investigate in detail stars moving at a source (not a gravity of a regular material like fixed stars) constantly high velocity in our galaxy. NAOJ will observe by a phenomenon called flat rotation where the orbital the distance and orbital velocity of more stars, trying to velocity of stars is maintained evenly regardless of the determine the distribution of the dark matter. distance between the stars and the center of our galaxy. The 8-m Subaru Telescope remarkably contributes In addition, nothing seems more persuasive than the dark to development of observational cosmology, with its matter when it comes to explaining why high temperature spectrograph and wide-field imager that is the only camera gas in galaxy clusters can remain bound to the cluster and mounted among similar-sized telescopes to Subaru. To why lights are inflected more greatly than by the gravity investigate the dark energy and dark matter more closely, of the galaxy (gravitational lens effect). we started a project to fabricate Hyper Suprime-Cam, a It gradually became known that the dark energy must camera with an even wider view filed than the current exist, as universal repulsion, three times the mass of the imager. This project, in collaboration with Princeton gravitational sources in the universe. This is derived University of the United States and Academia Sinica from the fact that the expansion velocity of the universe Institute of Astronomy and Astrophysics of Taiwan, is so is increasing at an accelerated pace, while gravitational comprehensive that it requires the upgrade of the Subaru sources are present in the universe (materials and dark Telescope itself as well. This camera is expected to dramatically accelerate the advancement of observational has actually started; Nobeyama Millimeter Array; and cosmology. In addition to the implementation of the Okayama Astrophysical Observatory. project, we successfully completed a new adaptive optics MIRA Project which was ranked as “A project” with near-diffraction-limit resolution for images obtained (projects in the early developmental stage) ended at by ground-based telescopes as well as a laser-guide the end of fi scal 2007 as the external review committee star system which artificially creates reference objects decided the continuous study by MIRA in Mitaka was not for the adaptive optics. The both satisfied the projected feasible. The other “A project,” 4-Dementional Digital performance. Universe (4D2U) Project also ended in fi scal 2007, while Computation simulation, which is of significance the development of its contents and public outreach for the studies of cosmology, revealed what type of activities will be continued, by Center for Computational dark matter is necessary to form the cosmic large- Astrophysics and by Public Relations Center respectively. scale structure. To analyze observational data, software Our public outreach activities have intensely been and hardware for data analysis need to be regularly promoted to provide the public with the information on maintained and upgraded. Thanks to the support from the astronomical achievements. The official website of many people concerned, the computer system and NAOJ has been successful with 50 million hit counts a instruments of NAOJ have been fully replaced, which are year. Astronomy-related questions asked of NAOJ were used for shared use, advance theoretical study, analyze answered in a more effective way, and the special open and establish database. day events at the observatories attracted more visitors Atacama Large Millimeter/submillimeter Array than previous years. (ALMA), an international project with Europe and Following the adoption of adjusting cost for the North America, is expected to benefit the advancement promotion of science and technology from Ministry of of the astronomical studies. ALMA is an array Education, Culture, Sports, Science and Technology, consisted of eighty antennas (7-m and 12-m antennas) Scientific Culture Formation Unit was established in including sixteen Japanese antennas and has been under collaboration with Mitaka City in fiscal 2007. The construction in Chile. NAOJ has delivered four 12-m Unit provides educational programs for those who antennas to the site in Chile ahead of the other two have been recruited and will promote scientific culture partners and took images of the moon in radio spectrum taking advantage of NAOJ’s scientific resources and with one of the antennas. The Japanese correlator was achievements. Scientific Culture Formation Unit has installed at the site and will combine signals transmitted started to support the students who try to establish new from the Japanese sixteen antennas. The development and business on their own. fabrication of the receivers for the antennas are steadily In terms of education, great efforts have been going on. made to provide excellent graduate education, nurture On top of the subjects mentioned above, there are young researchers, and improve academic research more challenging subjects of today’s astronomy: the environments. In such environments of NAOJ, 50 and discovery of extrasolar planets; the exploration of more graduate students and researchers engaged in extraterrestrial life; the advancement of solar science; the research activities. We will continuously make further explanation of undefined celestial materials like black efforts to educate and support young researchers. hole; the ascertainment of the structure of galaxies; and the unravelment of the forming process of galaxies, stars and planets. To explore these unanswered mysteries, the following activities have been continuously conducted: the development of the Subaru Telescope and its new device; Hinode, the observational satellite to study the sun; Kaguya, the moon exploration satellite which provides the new information on the moon; VSOP-2 Shoken MIYAMA (VLBI Space Observatory Programme-2) whose operation Director General of NAOJ I Scientific Highlights (April 2007 – March 2008) 01 Detection of coronal Alfvén waves in a solar prominence with Hinode OKAMOTO et al. 003 02 Small-Scale Jetlike Features in Penumbral Chromospheres KATSUKAWA et al. 004 03 Behavior of Lithium Abundances in Solar-Analog Stars TAKEDA et al. 005 Fine Structures of Solar X-Ray Jets Observed with protect the X-Ray 04 SHIMOJO et al. 006 Telescope aboard Hinode 05 First Results from the Hinode/SOT Helioseismology Programme NAGASHIMA et al. 007 06 Dynamic formation of the magnetic structure of a solar prominence MAGARA 008 07 Supernova Mixtures Reproducing Isotopic Ratios of Presolar Grains YOSHIDA 009 08 ν-Process Nucleosynthesis in Population III Core-Collapse Supernovae YOSHIDA et al. 010 The Habitat Segregation between Lyman Break Galaxies and Lyman α 09 KASHIKAWA et al. 011 Emitters around a QSO at z ~ 5 10 First Measurement of Meteoroid Tunnel Size in Earth's Atmosphere IYE et al. 012 Active supermassive blackholes buried in ultraluminous infrared galaxies, 11 IMANISHI et al. 013 unveiled
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