NAKAMURA Takashi Kyoto Univ., Yukawa Inst. Theor. Phys., Professor, 基礎物理学研究所, 教授 (80155837)
齊藤 芳男 高エネルギー加速器研究機構, 加速器第四系, 助教授 (00141979)
KURODA Kazuaki Univ. Tokyo, Inst. Cosmic Ray Research, Professor, 宇宙線研究所, 教授 (00242165)
FUJIMOTO Masa-katsu National Astronomical Observatory, Professor, 天体力学研究系, 教授 (90107475)
TUBONO Kimio Univ. Tokyo, Dep. Phys., Professor, 大学院・理学系, 教授 (10125271)
KANDA Nobuyuki Miyagi Univ. Education, Dep. Phys., Associate Prof., 教育学部, 助教授 (50251484)
Gravitational wave astronomy has a potential to bring us new informations about supernovae, coalescence of binary neutron stars or binary black holes, or early stage of the Universe, which cannot be obtained by other means of observation such as electromagnetic waves, neutrino, and so on. Nobody has yet succeeded to detect gravitational waves. However, it seems possible in the near future to detect a realistic gravitational wave from an extraterrestrial origin, by developing sensitive and stable laser interferometers with very long arms.
In this study, a sensitive laser interferometer with two 300m long arms, TAMA300, has been developed and constructed on Mitaka campus of the National Astronomical Observatory, for the purpose to establish technologies for realizing a km-scale laser interferometer, and has been operated as a telescope to watch for a chance to detect a gravitational wave generated within nearby galaxies.
We have succeeded to develop a high-power and ultra-stable laser, very high quality mirrors and so on, which are all essential to the high sensitive interferometer. In the summer of 1999, we performed the first observational run successfully in advance of the other large-scale laser interferometers around the world, LIGO (4km) in USA, VIRGO(3km) collaboration between French and Italy, and GEO(600m) collaboration between England and Germany. In the summer of 2000, TAMA300 has reached a top-level sensitivity and has demonstrated a sufficient capability to detect a gravitational wave from a coalescence of binary neutron stars within our Galaxy. In the summer of 2001, we performed a long-term scientific run for 50 days and obtained the observational data for more than 1000 hours. After the run, we have installed a power-recycling mirror to the interferometer, and succeeded to operate it in a short time.
In the coming years, coincident runs of TAMA300 with LIGO and GEO are planned to make a global network for the gravitational-wave search.