The Japanese Space Gravitational Wave Antenna - DECIGO

Amaldi7 @Sydney, AustraliaJuly 12, 2007

Seiji KAWAMURA, Masaki ANDO, Takashi NAKAMURA, Kimio TSUBONO, Takahiro TANAKA, Ikkoh FUNAKI, Naoki SETO, Kenji NUMATA, Shuichi SATO, Kunihito IOKA, Nobuyuki KANDA, Takeshi TAKASHIMA, Kazuhiro AGATSUMA, Tomomi AKUTSU, Tomotada AKUTSU, Koh-suke AOYANAGI, Koji ARAI, Yuta ARASE, Akito ARAYA, Hideki ASADA, Yoichi ASO, Takeshi CHIBA, Toshikazu EBISUZAKI, Motohiro ENOKI, Yoshiharu ERIGUCHI, Feng-Lei HONG, 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, Hideyuki HORISAWA, Mizuhiko HOSOKAWA, Kiyotomo ICHIKI, Takeshi IKEGAMI, Kaiki T. INOUE, Koji ISHIDOSHIRO, Takehiko ISHIKAWA, Hideharu ISHIZAKI, Hiroyuki ITO, Yousuke ITOH, Shogo KAMAGASAKO, Nobuki KAWASHIMA, Fumiko KAWAZOE, Hiroyuki KIRIHARA, Naoko KISHIMOTO, Kenta KIUCHI, Werner KLAUS, 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, Jun-ichi MIURA, 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, Tadayuki TAKAHASHI, Ryutaro TAKAHASHI, Ryuichi TAKAHASHI, Kakeru TAKAHASHI, Hirotaka TAKAHASHI, Akiteru TAKAMORI, 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

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

Inflation

Formation of Super-

massive BH

Verification of inflation

Science by DECIGO

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)

Pre-DECIGODECIGO

R&DFabrication

R&DFabrication

R&DFabrication

Pre-conceptual design and objectives of DPF

ThrusterLocal

Sensor

Floating mirrorRigidCavity

Laser

Actuator

Test of drag-free system

Test of locking system in space

Test of laser in space

Test of frequency stabilization

system in space

Observation of GW at 0.1 – 1 Hz

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) was rejected.

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

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

• We will submit budget request (R&D for DPF, $200K) to JAXA/ISAS.

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 been and will be working hard to obtain a budget to initiate R&D for DECIGO and DPF.

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

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