The Japanese Space Gravitational Wave Antenna - DECIGO

Amaldi6 @OkinawaJune 22, 2005

Seiji Kawamura, Takashi Nakamura, Masaki Ando, Kimio Tsubono, Naoki Seto, Shigeo Nagano, Takahiro Tanaka, Takehiko Ishikawa, Ken-ichi Ueda, Mitsuru Musha, Takashi Sato, Mizuhiko Hosokawa, Kenji Numata, Hisashi Hirabayashi, Tadashi Takano, Masa-Katsu Fujimoto, Atsushi Taruya, Yoshiaki Himemoto, Chul-Moon Yoo, Kenichi Nakao, Tomohiro Harada, Kunihito Ioka, Norichika Sago, Wataru Hikida, Shuichi Sato, Keiko Kokeyama, Mitsuhiro Fukushima, Hiroo Kunimori, Toshitaka Yamazaki, Masashi Ohkawa, Tatsuaki Hashimoto, Koh-suke Aoyanagi, Kazuhiro Agatsuma, Tomotada Akutsu, Hideki Asada, Yoichi Aso, Koji Arai, Akito Araya, Takeshi Ikegami, Koji Ishidoshiro, Kiyotomo Ichiki, Yousuke Itoh, Kaiki T. Inoue, Yoshiharu Eriguchi, Naoko Ohishi, Masatake Ohashi, Kenichi Oohara, Akira Okutomi, Shogo Kamagasako, Nobuki Kawashima, Mari Kawamura, Nobuyuki Kanda, Katsuhiko Ganzu, Kenta Kiuchi, Hideaki Kudoh, Kazuaki Kuroda, Kazunori Kohri, Yoshihide Kozai, Yasufumi Kojima, Shiho Kobayashi, Motoyuki Saijo, Masaaki Sakagami, Shihori Sakata, Misao Sasaki, Masaru Shibata, Hisaaki Shinkai, Naoshi Sugiyama, Hajime Sotani, Hirotaka Takahashi, Ryuichi Takahashi, Ryutaro Takahashi, Hideyuki Tagoshi, Hiroyuki Tashiro, Keisuke Taniguchi, Takeshi Chiba, Shinji Tsujikawa, Yoshiki Tsunesada, Masao Tokunari, Isao Naito, Hiroyuki Nakano, Kouji Nakamura, Atsushi Nishizawa, Yoshito Niwa, Choetsu Nozawa, Kazuhiro Hayama, Takashi Hiramatsu, Toshifumi Futamase, Kei-ichi Maeda, Hideo Matsuhara, Hiromi Mizusawa, Yasushi Mino, Osamu Miyakawa, Shinji Miyoki, Shinji Mukohyama, Toshiyuki Morisawa, Kazuhiro Yamamoto, Jun'ichi Yokoyama, Shijun Yoshida, and Taizoh Yoshino

Contents

1. What is DECIGO?2. Current Status3. Budget Situation4. Preliminary Experiment5. Summary

Gap between TerrestrialDetectors and LISA

10-

18

10-

24

10-

22

10-

20

10-

4

104

102

100

10-

2Frequency [Hz]

Str

ain

[H

z-1

/2]

LISA Terrestrial Detectors (e.g. LCGT)

Gap

DECIGO Bridges the Gap

10-

18

10-

24

10-

22

10-

20

10-

4

104

102

100

10-

2Frequency [Hz]

Str

ain

[H

z-1

/2]

LISA

DECIGO

Terrestrial Detectors (e.g. LCGT)

The Japanese Space Gravitational Wave Antenna - DECIGODeci-hertz Interferometer Gravitational Wave Observatory　

Importance of Bridgingthe Gap

New window brings new science! Observe inspiral sources that have moved a

bove the LISA band Observe inspiral sources that have not yet

moved into the ground-based detector band Especially inspiral of IMBH Completely new sources could be detected Completely new science could be obtained

Acceleration of Expansion of the Universe

NS-NS (z～1)

GW

DECIGO

Output

Expansion ＋Acceleration?

Time

Str

ai

n

Template (No Acceleration)

Real Signal ? Phase Delay～ 1sec (10

years)Seto, Kawamura, Nakamura, PRL 87, 221103 (2001)

DECIGO as a Future Gravitational Wave

Detection Project in Japan

TAMA

Near Future

NowPast

DECIGO

LCGT

Far Future

1st Priority

History of DECIGO1999 the LISA study group convened by Tsubono2000 Short-arm space antenna suggested by Kawam

ura2001 Space GW antenna WG convened as one of the

possible future projects in NAOJ2001 Named as DECIGO in the PRL paper by Seto,

Kawamura, Nakamura (DECIDE and GO)2002 1st DECIGO-WG meeting2003 2nd DECIGO-WG meeting

(FP-type DECIGO suggested by Ando)2005 3rd DECIGO-WG meeting

Roadmap for DECIGO06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Design & Fabrication

Observation

R&D

Advanced R&D

PF1

DECIGO

Design & Fabrication

Observation

PF2

Pre-Conceptual Designfor DECIGO

LISA-type DECIGO- Shorter arm length

Fabry-Perot-Cavity-type DECIGO- Even shorter arm length- Resonance of light in the cavity

For both types- Better shot noise (higher power, shorter wavelength, larger mirror)- Better force noise (heavier mass)

Fabry-Perot Type DECIGO

Drag-Free Satellite

Around Lagrange Point Fabry-Perot

cavity

Actuating Force in FP-DECIGO

Anti-Drag + Anti-Gravity +Anti-GW

Anti-Gravity +Anti-GW

Proof Mass

Outer Satellite

The distance should

be kept constant

Sensitivity of DECIGO

Force noise= 1/100 of LISA’s

10–4 10–3 10–2 10–1 100 101 102 10310–25

10–24

10–23

10–22

10–21

10–20

10–19

10–18

Frequency [Hz]

Str

ain

[

1/H

z1/2]

LCGT

LISA

DECIGO(LISA type, 5x104km)

DECIGO(FP type, 1000km)

Laser: 10W, 532nmMass: 100kgMirror: 1m dia.

Preliminary Simulatorfor LISA-type DECIGO

Built a preliminary simulator for DECIGO as a simulator for detecting the Earth’s gravity field around the Earth

地球

Distance: 50 km

vMAX: 1 cm/s（ Doppler Shift: 20 kH

z

Satellite 2Satellite 1

Schematic Diagram ofthe Preliminary Simulator

Simulate Doppler shift by AOD

Simulate distance by optical fiber

Lock to mid-fringe by AOD

Monitor FB to DDS

Stabilized Frequency using 5 layer shielded cavity (like LISA)

Sensitivity ofthe Preliminary Simulator

Budget Situation for DECIGO

and other GW Projects in JapanBudget request for “Frontier of

All Wavelength Gravitational Wave Astronomy” to be submitted this fall- TAMA and CLIO- R&D for DECIGO- Pulsar Timing- Super-high frequency G.W. detection

(Budget request for LCGT submitted this year from ICRR)

R&D for DECIGO

Overall Tests

Key Technologies

Ground-based DECIGO

Simulator(S. Kawamura, NAOJ)

DECIGO-Pathfinder (M. Ando, Univ. of Tokyo)

Measurement System

(K. Tsubono,Univ. of Tokyo)

Drag-freeSystem

(T. Ishikawa,

JAXA-ISAS)

Light Source

(K. Ueda, ILS)

Frequency Stabilizati

on(T. Sato,Niigata Univ.)

Evaluation of Light Source

(M. Hosokawa,

NICT)

Satellite Technologie

s(?, JAXA-

ISAS)

Objectives of the R&D

R&D of subsystemsOverall tests by ground-based

simulator and DECIGO-Pathfinder1R&D for optional technologiesDefining the objectives and

conceptual design of DECIGO-PF2Establishing the conceptual

design of DECIGO

Ground-Based Simulater

Laser

LF Pendulum

Seismic Isolation System Seismic Isolation System

Test the system on earth as much as possible Investigate the system at low frequencies Observe GW at low frequenciesLF Pendulum

Pathfinder Test the system which can be tested only in space (Drag-f

ree system) Check if the measurement system works in space Observe GW at low frequencies This effort couples with the JAXA-ISAS’s new satellite plan

Laser

Drag Free System

Measurement System

One Small Satellite

Resonated

Summary It is important to bridge the gap

between terrestrial detectors and LISA.

The Japanese space antenna DECIGO can bridge the gap.

We have started serious investigation of DECIGO.

We will submit a budget request for DECOGO R&D this fall.

We hope that we will be able to start the R&D for DECIGO soon.