Research Activities
Research Subjects Experimental Relativity, Gravitational Wave, Laser Interferometer
The detection of gravitational waves is expected to open a new window into the universe and
brigns us a new type of information about catastrophic events such as supernova or coalescing binary neutron starts;
these information can not be obtained by other means such as optics, radio-waves or X-ray.
Worldwide efforts are being continued in order to construct detectors with sufficient sensitiviy to catch possible
gravitational waves. Now the detection of the gravitational waves is one of the biggest challenges in the field pf physics and astronomy.
TAMA300 is a 300-m baseline lasetr interferometric gravitational wave detector constructed in Mitaka.
We started the operation of the detection in 1999. The achieved sensitivity, h=3x10^-21 [1/rHz] at 700Hz to 1.5kHz, is
sufficient to catch possible gravitaitonal wave events in our galaxy. We can operate the detector
for over 24 hours stably and continuously, and have accumulated over 3,000 hours data. We are now
analyzing the obtained data searching for the gravitational waves from coalescing binaries, supernovae and pulsars.
A space laser interferometer, DECIGO, was proposed through the study of the gravitational wave sources with
cosmological origin. DECIGO could detect primordial gravitational waves from the early Universe at the inflation era.
We have just started the theoritical and technical investigation for the realiation of the DECIGO space detector.
We summarize the subjects being studied in our group.
- Laser interferometric gravitational wave detectors
- Space gravitational wave detectors
- Space Laser interferometer, DECIGO [3]
- DECIGO pathfinder
- SpaceWire Interface demonstration Module, SWIM
- Development of an ultra-small-scale gravitational-wave detector, SWIMmunu
- Study of the precise measurements
- Laser stabilization using optical fiber [4]
- Torsion pendulum using the flux pinning effect on a superconductor
- Suspension point interferometer for vibration isolation [5]
- Study of the themal noise
- Study of the theram noise in a space interferometer
- A new analysis method for the theraml noise caused by an inhomogeneous distributed loss [6]
Reference
[1] Daisuke Tatsumi et al., Glass. Quantum Grav. 24 19 S399 (2007)
[2] Koji Ishidoshiro, Masaki Ando, Kimio Tsubono, Nobuyuki Kanda and Hirotaka Takahashi, Glass. Quantum Grav. 24 19 S405 (2007)
[3] Seiji Kawamura et al., Glass. Quantum Grav. 23 8 S125 (2006)
[4] Kakeru Takahashi, Masaki Ando and Kimio Tsubono, submitted to Journal of Physics: Conference Series
[5] Youichi Aso, Ph.D. thesis, University of Tokyo, 2006
[6] Kazuhiro Yamamoto, Masaki Ando, Keita Kawabe and Kimio Tsubono, Physical Review D, 75 082002 (2007)
For those who want to read the brief reports on the activity of Tsubono-group,
the following is a part of the Annual Report of the Department of Physics, University of Tokyo.
