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