The Japanese Space Gravitational Wave Antenna DECIGO

TAUP2007 @Sendai, JapanAug 11, 2007

Seiji Kawamura, Masaki Ando, Takashi Nakamura, Kimio Tsubono, Takahiro Tanaka, Ikkoh Funaki, Naoki Seto, Kenji Numata, Shuichi Sato, Nobuyuki Kanda, Takeshi Takashima, Kunihito Ioka, Kazuhiro Agatsuma, Tomotada Akutsu, Tomomi Akutsu, Koh-suke Aoyanagi, Koji Arai, Yuta Arase, Akito Araya, Hideki Asada, Yoichi Aso, Takeshi Chiba, Toshikazu Ebisuzaki, Motohiro Enoki, Yoshiharu Eriguchi, Masa-Katsu Fujimoto, Ryuichi Fujita, Mitsuhiro Fukushima, 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, Koji Ishidoshiro, Hideki Ishihara, Takehiko Ishikawa, Hideharu Ishizaki, Hiroyuki Ito, Yousuke Itoh, Shogo Kamagasako, Nobuki Kawashima, Fumiko Kawazoe, Hiroyuki Kirihara, 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, Noriyasu Nakagawa, Kouji Nakamura, Hiroyuki Nakano, Kenichi Nakao, Shinichi Nakasuka, Yoshinori Nakayama, Erina Nishida, Kazutaka Nishiyama, Atsushi Nishizawa, Yoshito Niwa, Masatake Ohashi, Naoko Ohishi, Masashi Ohkawa, Akira Okutomi, Kouji Onozato, Kenichi Oohara, Norichika Sago, Motoyuki Saijo, Masaaki Sakagami, Shin-ichiro Sakai, Shihori Sakata, Misao Sasaki, Takashi Sato, Masaru Shibata, Hisaaki Shinkai, Kentaro Somiya, Hajime Sotani, Naoshi Sugiyama, Yudai Suwa, Hideyuki Tagoshi, Kakeru Takahashi, Keitaro Takahashi, Tadayuki Takahashi, Hirotaka Takahashi, Ryuichi Takahashi, Ryutaro Takahashi, Takamori Akiteru, Tadashi Takano, Keisuke Taniguchi, Atsushi Taruya, Hiroyuki Tashiro, Mitsuru Tokuda, Masao Tokunari, Morio Toyoshima, Shinji Tsujikawa, Yoshiki Tsunesada, Ken-ichi Ueda, Masayoshi Utashima, Hiroshi Yamakawa, Kazuhiro Yamamoto, Toshitaka Yamazaki, Jun'ichi Yokoyama, Chul-Moon Yoo, Shijun Yoshida, Taizoh Yoshino

What is DECIGO?Deci-hertz Interferometer Gravitational Wave Observatory

(Kawamura, et al., CQG 23 (2006) S125-S131) Bridges 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

have moved

Above LISA bandwill move

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

Inflation

Formation of Super-

massive BH

Verification of inflation

Goal Sensitivity and Science

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

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.

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 technologies 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) Ando’ s talk

Pre-DECIGODECIGO

R&DFabrication

R&DFabrication

R&DFabrication

Interim organizationPI: Kawamura (NAOJ)Deputy: Ando (Tokyo)

Executive CommitteeKawamura (NAOJ), Ando (Tokyo), Seto (NAOJ), Nakamura (Kyoto), Tsubono (Tokyo), Tanaka (Kyoto), Funaki (ISAS), Numata (Merryland), Sato

(NAOJ), Kanda (Osaka city), Takashima (ISAS), Ioka (Kyoto)

Pre-DECIGO

Sato (NAOJ)

Satellite

Funaki (ISAS)

Science, Data

Tanaka (Kyoto)Seto (NAOJ)

Kanda (Osaka city)

DECIGO pathfinderLeader: Ando (Tokyo)

Deputy: Takashima (ISAS)

Detector

Ando (Tokyo)

Housing

Sato (NAOJ)

Laser

Ueda (ILS)Musya (ILS)

Drag free

Moriwaki (Tokyo)

Sakai (ISAS)

Thruster

Funaki (ISAS)

Bus

Takashima (ISAS)

Data

Kanda (Osaka city)

Detector

Numata (Merryland)

Ando (Tokyo)

Mission phase

Design phase

Current status

• There are now 140 members from 50 institutes in DECIGO working group

• Budget request (DECIGO R&D and fabrication of DPF, $20M, 6 years) was rejected.

• We will submit budget request (R&D for DECIGO and DP, $10M, 5-6 years) this year again.

• DPF working group was formally approved by JAXA/ISAS.

• Budget request (R&D for DPF, $65K, 1 year) to JAXA/ISAS was approved.

Summary DECIGO can not only bridge the gap

between terrestrial detectors and LISA, but also open a very deep window at 0.1 – 10 Hz.

DECIGO will use FP arm cavity to further improve the sensitivity.

We have obtained some budget to initiate R&D for DPF.

We hope that we will obtain a bigger budget for DECIGO R&D, and that DPF mission will be approved soon!

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)

Ground-based simulator(juggling interferometer)

Mo

ving

up

and

d

ow

n

Time

Po

siti

on

~ 2

m

Re

lea

se H

old

Co

ntin

ually

Freely fallin

g

~ 1 secClamp

Realize continual free-fall condition Measure force noise Test clamp release system High GW sensitivity at 0.1 – 10 Hz Might be applied to future terrestrial

detectorsR

ele

as

e Ho

ld

Re

lea

se H

old

Fortune Cookie

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

a2001 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 DECIGO suggested by Ando)2005 3rd DECIGO workshop2006 4th DECIGO workshop

(FP-type DECIGO adopted as a pre-conceptual design)

2007 5th DECIGO workshop