Sora

CaJAGWR Seminar

July 29, 2008 @Caltech

Seiji Kawamura

(National Astronomical Observatory of Japan)

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

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.

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

Conceptual design and Technologies to demonstrate

Thruster

Local Sensor

Floating mirrorStabilization

system

Laser

Actuator

Drag-free control system Laser source and stabilization system Control of Fabry-Perot interferometer Launch-lock system

Goal sensitivity of DPF

10–2 10–1 100 101 10210–18

10–17

10–16

10–15

10–14

10–13

10–12

10–11

10–19

10–18

10–17

10–16

10–15

10–14

10–13

10–12

No

ise

lev

el

[1

/Hz1/

2 ]

Frequency [Hz]

Shot noise

Mirror thermal

Laser Radiation

Laser: 1064nm, 25mWFinesse: 100Mirror mass: 1kgQ–value of a mirror: 10 6

Cavity length: 10cm

pressure noise

Thruster noise

PM acceleration Noise

Geogravity

Laser Frequencynoise

Dis

pla

ce

me

nt

No

ise

[m

/Hz1/

2 ]

Expected sources

103 104 105 10610–1

100

101

102

Ob

serv

able

Ran

ge

Mass [Msolar]

[kp

c, S

NR

=5

]

Galactic Center

BH QNM

BH Inspiral

DPF S/C

Size : 900mm cubeWeight : 200kgSAP : 800W Battery: 50AHDownlink : 2MpbsDR: 1GByte3N Thrusters x 4

Stabilized Laser

Interferometer Module

Thruster Control Unit

Solar Paddle

Interfererometer Control Unit

Housing Control Unit

Mission Thrusters

Central Processing Unit

Bus Thrusters

Satellite Bus (‘Standard bus’ system)

DPF PayloadSize : 900mm cubeWeight : 100kgPower : 200WData Rate: 600kbpsMission thruster x16

Power SupplySpW Comm.

DPF Mission Outline

Orbit: Low-Earth (Altitude 500km), Sun-synchronous orbit (dusk-dawn)

Launcher: Single launch by M-V follow-on (solid rocket booster under development) PBS (Post-Boost stage) for fine orbit insertion

Launch: 2012 (target)Mission Lifetime: 1 year (nominal)

500km

DP

F

Attitude Control: Gravity-gradient stab. Drag-free control with mission thrusters (Safe hold control by bus thrusters)

DPF Payload

Fabry-Perot interferometer 　 Finesse : 100 　 Length : 20cm 　 Test mass : 1kg Signal extraction by PDH

Laser source Nd:YAG laser (1064nm) Power : 25mW Freq. stab. by reference cavity

Drag-free control Local sensor signal 　　 Feedback to mission thrusters

Weight : ~100 kgSize : ~90 cm cube

Upper half of the satellite

JAXA’s Small satellite seriesPlan to launch 3 small satellites by the year 2015 using next-generation solid rocket booster Reduce time and cost by means of ‘Standard bus system’

Bus weight : ~ 200kg, Bus power : ~ 800W 　 Downlink ~ 2Mbps, Data storage ~ 1GByte 3-axes attitude control SpaceWire-based data processing system

1st mission (2011) : decided to be TOPS (Planetary science)

2nd and 3rd mission will be selected by 2009 March

15 Candidate missions (5 important candidates) DPF: GW observation DIOS: X-ray telescope for dark baryon investigation ERG: Plasma and particle detector for geo-space investigation Satellite for Magnet-plasma sail technology demonstration, …

Image CG of TOPS (design has been changed now)

DPF Current status

Laser frequency stabilizationMirror and its housing Micro thrusterDrag-free control simulationDetailed design and noise investigation

Required to submit Phase-A proposal

R&D for core technologies

DPF Launch: 2012 or 2013 as 2nd or 3rd standard small satellite of JAXA

2005  Jan. 　 Submit a proposal of small GW detector mission2006 Nov. 　 Submit a proposal of GW-detector satellite as DECIGO pathfinder (DPF)2007 Aug. Selected as a Pre-Phase-A mission R&D costs funded

Brief History

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

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

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

(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 (IL

S)

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

1st InternationalLISA-DECIGO Workshop

• Nov. 12-13, 2008 @ ISAS, Sagamihara, Japan• Objectives:

– Mutual understanding– Possible collaboration– Exposure of the missions to people in the neighboring fields

• Plenary talks:– Science of LISA & DECIGO, status of LPF & DPF

• 1st circular w/ web page will be ready on Aug. 1

Summary

• DECIGO can detect GWs from the inflation as well as can bring us extremely interesting science.

• DPF has been selected as one of the 5 important mission candidates for small science satellite series; they plan to launch 3 missions in 5 years starting from 2011.

Let DPF fly!