Sora
1st LISA-DECIGO international workshop
Nov. 12, 2008 @ISAS/JAXA
Seiji Kawamura
(National Astronomical Observatory of Japan)
What is DECIGO?Deci-hertz Interferometer Gravitational Wave Observatory
Japanese space GW antenna to be launched after LISA
Can bridge the gap between LISA and terrestrial detectors
Low confusion noise -> Extremely high sensitivity
10-18
10-24
10-22
10-20
10-4 10410210010-2
Frequency [Hz]
Str
ain
[H
z-1/2]
LISA
DECIGO
Terrestrial detectors (e.g. LCGT)
Confusion Noise
moved above
LISA band To be moved
into TD band
Pre-conceptual designDifferential FP interferometer
Arm length: 1000 kmMirror diameter: 1 mLaser wavelength : 0.532 mFinesse: 10Laser power: 10 WMirror mass: 100 kgS/C: drag free3 interferometers
Laser
Photo-detector
Arm cavity
Drag-free S/C
Arm cavity
Mirror
Why FP cavity?
Frequency
Str
ain
Radiation pressure
noise f -2
Shot noiseShot n
oise
f1Transponder type(e.g. LISA)
Shot noise
Shortenarm length
Shot nois
e f1
Radiation pressure
noise f -2
Transponder type(e.g. LISA) Shorten
arm length Implement FP cavity
Implement FP cavity
FP cavity type Better best- sensitivity
Drag free and FP cavity: compatible?
Mirror
S/C IS/C II
FP cavity and drag free : compatible?
Local sensor
ThrusterThruster
Mirror
Relative position between mirror
and S/C
S/C II S/C I
Drag free and FP cavity: compatible?
Local sensor
ThrusterThruster
Mirror
Relative position between mirror
and S/C
Actuator
Interferometer output (GW signal)
S/C II S/C I
No signalmixture
Orbit and constellation (preliminary)
Sun
Earth
Record disk
Increase angular resolution
Correlation for stochastic background
Science by DECIGO
Inflation
Formation of Super-
massive BH
Verification of inflation
Frequency [Hz]
Correlation(3 years)
Str
ain
[H
z-1/ 2]
10-3 10-2 10-1 1 10 102 103
10-19
10-20
10-21
10-22
10-23
10-24
10-25
10-26
(1000 M◎ z=1)
BH binary
Coalescence
5 years
NS binary (z=1)
Coalescence
3 months
Acceleration of Universe
⇓Dark energy
Radiation pressure noise
Shot noise
1 unit
Seto’s Talk for details
Acceleration of Expansion of the Universe
NS-NS (z ~ 1)GW
DECIGO
Output
Expansion + Acceleration?
Time
Str
ain
Template (No Acceleration)
Real Signal ?Phase Delay ~ 1sec (10 years)
Seto, Kawamura, Nakamura, PRL 87, 221103 (2001)
Requirements Acceleration noise should be suppressed below
radiation pressure noise– Force noise: DECIGO = LISA/50
(Acceleration noise in terms of h: 1, Distance: 1/5000, Mass: 100)
– Fluctuation of magnetic field, electric field, gravitational field, temperature, pressure, etc.
Sensor noise should be suppressed below shot noise.– Phase noise: DECIGO = LCGT×10
(Sensor noise in terms of h: 1, storage time: 10)– Frequency noise, intensity noise, beam jitter, etc.
Thruster system should satisfy range, noise, bandwidth, and durability.
Important Requirements[Practical force noise]4x10-17 N/Hz per mirror
[Frequency Noise] @ 1 HzFirst-stage stabilization : 1 Hz/HzStabilization gain by common-mode
arm length : 105
Common-mode rejection ratio : 105
Roadmap200
708 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
Missio
nO
bjectives
Test of key technologiesObservation run of GW
Detection of GW w/ minimum spec.Test FP cavity between S/C
Full GW astronomy
Sco
pe
1 S/C1 arm
3 S/C1 interferometer
3 S/C,3 interferometer3 or 4 units
DICIGO Pathfinder(DPF)
Pre-DECIGODECIGO
R&DFabrication
R&DFabrication
R&DFabrication
DECIGO Pathfinder (DPF)
Laser
PD
Floating Mirrors
Drag-free S/C
DECIGO DPF
20 cm
1,000 km
Shrink the arm lengthfrom 1,000 km to 20 cm
Ando’s Talk for details
Pre-DECIGOPre-DECIGO
DECIGO
Arm length 100 km 1000 km
Mirror diameter 30 cm 1 m
Laser wavelength 0.532 m 0.532 m
Finesse 30 10
Laser power 1 W 10 W
Mirror mass 30 kg 100 kg
# of interferometers in each cluster
1 3
# of clusters 1 4
Sensitivity of Pre-DECIGO
10-24
10-23
10-22
10-21
10-20
10-19
10-18
10-17
10-16
10-15
Str
ain
sen
siti
vit
y [
1/r
Hz]
10-3
10-2
10-1
100
101
102
103
Frequency [Hz]
DPFDPFDPFDPF
NS-NS inspiral (@300Mpc)
pre-DECIGO
DECIGO
S/N~14 for NS-NS@300Mpc, 10-20 events/year
History of DECIGO1999 the LISA study group convened by Tsubono2000 Short-arm space antenna suggested by Kawamu
ra2001 Space GW antenna WG convened as one of the
possible future projects in NAOJ2001 Named as DECIGO in the PRL paper2002 1st DECIGO workshop2003 2nd DECIGO workshop
(FP-type suggested by Ando)2005 3rd DECIGO workshop2006 4th DECIGO workshop
(FP-type adopted as a pre-conceptual design)2007 5th DECIGO workshop2008 6th DECIGO workshop
1st LISA-DECIGO workshop
Interim organizationPI: Kawamura (NAOJ)Deputy: Ando (Tokyo)
Executive CommitteeKawamura (NAOJ), Ando (Tokyo), Seto (NAOJ), Nakamura (Kyoto), Tsubono (Tokyo), Tanaka (Kyoto), Funaki (ISAS), Numata (Maryland), Sa
to (Hosei), Kanda (Osaka city), Takashima (ISAS), Ioka (Kyoto)
Pre-DECIGO
Sato (Hosei)
Satellite
Funaki (ISAS)
Science, Data
Tanaka (Kyoto)Seto (NAOJ)
Kanda (Osaka city)
DECIGO pathfinderLeader: Ando (Tokyo)
Deputy: Takashima (ISAS)
Detector
Ando (Tokyo)
Housing
Sato (Hosei)
Laser
Ueda (ILS)
Musya (ILS)
Drag free
Moriwaki (Tokyo)
Sakai (ISAS)
Thruster
Funaki (ISAS)
Bus
Takashima (ISAS)
Data
Kanda (Osaka
city)
Detector
Numata (Maryland)
Ando (Tokyo)
Mission phase
Design phase
DECIGO-WGKazuhiro Agatsuma, Masaki Ando, Koh-suke Aoyanagi, Koji Arai, Akito Araya, Hideki Asada, Yoichi Aso, Takeshi Chiba, Toshikazu Ebisuzaki, Yumiko Ejiri, Motohiro Enoki, Yoshiharu Eriguchi, Masa-Katsu Fujimoto, Ryuichi Fujita, Mitsuhiro Fukushima, Ikkoh Funaki, Toshifumi Futamase, Katsuhiko Ganzu, Tomohiro Harada, Tatsuaki Hashimoto, Kazuhiro Hayama, Wataru Hikida, Yoshiaki Himemoto, Hisashi Hirabayashi, Takashi Hiramatsu, Feng-Lei Hong, Hideyuki Horisawa, Mizuhiko Hosokawa, Kiyotomo Ichiki, Takeshi Ikegami, Kaiki T. Inoue, Kunihito Ioka, Koji Ishidoshiro, Hideki Ishihara, Takehiko Ishikawa, Hideharu Ishizaki, Hiroyuki Ito, Yousuke Itoh, Nobuyuki Kanda, Seiji Kawamura, Nobuki Kawashima, Fumiko Kawazoe, Naoko Kishimoto, Kenta Kiuchi, Shiho Kobayashi, Kazunori Kohri, Hiroyuki Koizumi, Yasufumi Kojima, Keiko Kokeyama, Wataru Kokuyama, Kei Kotake, Yoshihide Kozai, Hideaki Kudoh, Hiroo Kunimori, Hitoshi Kuninaka, Kazuaki Kuroda, Kei-ichi Maeda, Hideo Matsuhara, Yasushi Mino, Osamu Miyakawa, Shinji Miyoki, Mutsuko Y. Morimoto, Tomoko Morioka , Toshiyuki Morisawa, Shigenori Moriwaki, Shinji Mukohyama, Mitsuru Musha, Shigeo Nagano, Isao Naito, Kouji Nakamura, Takashi Nakamura, Hiroyuki Nakano, Kenichi Nakao, Shinichi Nakasuka, Yoshinori Nakayama, Kazuhiro Nakazawa, Erina Nishida, Kazutaka Nishiyama, Atsushi Nishizawa, Yoshito Niwa, Kenji Numata, Masatake Ohashi, Naoko Ohishi, Masashi Ohkawa, Kouji Onozato, Kenichi Oohara, Norichika Sago, Motoyuki Saijo, Masaaki Sakagami, Shin-ichiro Sakai, Shihori Sakata, Misao Sasaki, Shuichi Sato, Takashi Sato, Naoki Seto, Masaru Shibata, Hisaaki Shinkai, Kentaro Somiya, Hajime Sotani, Naoshi Sugiyama, Yudai Suwa, Rieko Suzuki, Hideyuki Tagoshi, Fuminobu Takahashi, Kakeru Takahashi, Keitaro Takahashi, Ryutaro Takahashi, Ryuichi Takahashi, Tadayuki Takahashi, Hirotaka Takahashi, Takamori Akiteru, Tadashi Takano, Takeshi Takashima, Takahiro Tanaka, Keisuke Taniguchi, Atsushi Taruya, Hiroyuki Tashiro, Mitsuru Tokuda, Yasuo Torii, Morio Toyoshima, Kimio Tsubono, Shinji Tsujikawa, Yoshiki Tsunesada, Akitoshi Ueda, Ken-ichi Ueda, Masayoshi Utashima, Hiroshi Yamakawa, Kazuhiro Yamamoto, Toshitaka Yamazaki, Jun'ichi Yokoyama, Chul-Moon Yoo, Shijun Yoshida, Taizoh Yoshino
LCGT and DECIGO
Establish GW astronomy Develop GW astronomy
LCGT
DECIGO
CLIO DPF
Demonstration of technology Demonstration of technology
Budget request to MEXT• “Demonstration of science and
technologies for establishment of GW astronomy” (PI: Kawamura)
• Consists of 3 researches:– Ground-based detector (PI: Mio)– Space antenna (PI: Ando)– Theory, data analysis (PI: Kanda)
• $10M for 5 years• Application to be submitted soon
Summary• DECIGO can bridge the gap between LISA a
nd terrestrial detectors• DECIGO can detect GWs from the inflation a
s well as can bring us extremely interesting science.
• DECIGO uses a differential FP interferometer to enhance sensitivity
• We plan to launch DPF and Pre-DECIGO before DECIGO for demonstration of required technologies
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