1. Sora LISA8 @Stanford Univ. USA June 29, 2010 Seiji Kawamura, Masaki Ando, Naoki Seto, Shuichi Sato, Ikkoh Funaki, Takashi Nakamura, Kimio Tsubono, Jun'ichi Yokoyama, Kenji Numata, Nobuyuki Kanda, Takeshi Takashima, Takahiro Tanaka, Kunihito Ioka, Kazuhiro Agatsuma, Tomotada Akutsu, 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, Toshifumi Futamase, 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, Kiwamu Izumi, Isao Kawano, Nobuki Kawashima, Fumiko Kawazoe, Naoko Kishimoto, Kenta Kiuchi, Shiho Kobayashi, Kazunori Kohri, Hiroyuki Koizumi, Yasufumi Kojima, Keiko Kokeyama, Wataru Kokuyama, Kei Kotake, Yoshihide Kozai, Hiroo Kunimori, Hitoshi Kuninaka, Kazuaki Kuroda, Kei-ichi Maeda, Hideo Matsuhara, Nobuyuki Matsumoto, Yuta Michimura, Yasushi Mino, Osamu Miyakawa, Umpei Miyamoto, Shinji Miyoki, Mutsuko Y. Morimoto, Toshiyuki Morisawa, Shigenori Moriwaki, Shinji Mukohyama, Mitsuru Musha, Shigeo Nagano, Isao Naito, Kouji Nakamura, Hiroyuki Nakano, Kenichi Nakao, Shinichi Nakasuka, Yoshinori Nakayama, Kazuhiro Nakazawa, Erina Nishida, Kazutaka Nishiyama, Atsushi Nishizawa, Yoshito Niwa, Taiga Noumi, Yoshiyuki Obuchi, Masatake Ohashi, Naoko Ohishi, Masashi Ohkawa, Kenshi Okada, Norio Okada, Kenichi Oohara, Norichika Sago, Motoyuki Saijo, Ryo Saito, Masaaki Sakagami, Shin-ichiro Sakai, Shihori Sakata, Misao Sasaki, Takashi Sato, Masaru Shibata, Hisaaki Shinkai, Ayaka Shoda, 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, Nobuyuki Tanaka, Keisuke Taniguchi, Atsushi Taruya, Hiroyuki Tashiro, Yasuo Torii, Morio Toyoshima, Shinji Tsujikawa, Yoshiki Tsunesada, Akitoshi Ueda, Ken-ichi Ueda, Masayoshi Utashima, Kent Yagi, Hiroshi Yamakawa, Kazuhiro Yamamoto, Toshitaka Yamazaki, Chul-Moon Yoo, Shijun Yoshida, Taizoh Yoshino, Ke-Xun Sun

2. Outline Japanese GW Roadmap DECIGO Roadmap to DECIGO DECIGO Pathfinder, etc. Organization, Collaboration, etc. Summary

3. Japanese Roadmap to GW Astronomy Detecting GW (International network) LCGT DECIGO Opening a new window (after LISA) LCGT: $110M for 3 years approved! (Thanks to support from international GW community)

4. What is DECIGO? Deci-hertz Interferometer Gravitational Wave Observatory Bridges the gap between LISA and ground-based detectors Low confusion noise -> Extremely high sensitivity 10 -18 10 -24 10 -22 10 -20 10 -4 10 4 10 2 10 0 10 -2 Frequency [Hz] Strain [Hz -1/2 ] LISA DECIGO Ground-based detectors Confusion Noise moved above LISA band To be moved into GBD band

5. Pre-conceptual design Differential FP interferometer Arm length: 1000 km Mirror diameter: 1 m Laser wavelength ： 0.532  m Finesse: 10 Laser power: 10 W Mirror mass: 100 kg S/C: drag free 3 interferometers Laser Photo- detector Arm cavity Drag-free S/C Arm cavity Mirror

6. Why FP cavity? Frequency Strain Radiation pressure noise f -2 Shot noise Shot noise f 1 Transponder type Shot noise Shorten arm length Shot noise f 1 Radiation pressure noise f -2 Transponder type Shorten arm length Implement FP cavity FP cavity type Better shot- noise-limited sensitivity More stringent acceleration noise requirement

7. Drag free and FP cavity: compatible? Mirror S/C I S/C II Solar radiation pressure, etc Solar radiation pressure, etc Gravity force 1,000 km

8. FP cavity and drag free : compatible? Local sensor Thruster Mirror Relative position between mirror and S/C S/C II S/C I Gravity force

9. Drag free and FP cavity: compatible? Local sensor Thruster Mirror Relative position between mirror and S/C Actuator Interferometer output (GW signal) S/C II S/C I No signal mixture Gravity force

10. Orbit and constellation (preliminary) Sun Earth Record disk Increase angular resolution Correlation for stochastic background

11. Formation of super- massive BH Verification of inflation Science by DECIGO Frequency [Hz] Correlation (3 years) Strain [Hz -1/2 ] 10 -3 10 -2 10 -1 1 10 10 2 10 3 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 cluster Mini-black hole  Dark matter Brans Dicke parameter Inflation (  GW ~2×10 -16 )

12. Requirements Force noise of DECIGO should be 50 times more stringent than LISA –Acceleration noise in terms of h: comparable –Distance: 1/5000 –Mass: 100 Sensor noise of DECIGO should be10 times looser than LCGT –Sensor noise in terms of h: comparable, –Storage time: 10

13. Conceptual Design of DECIGO Optimize the design parameters to improve the sensitivity for the effective cleaning of the foreground –arm length, mirror diameter, mirror mass, laser power, finesse, etc. –Lead by Tomotada Akutsu Establish the design to realize the required performances –proof mass, mirror curvature, local sensor/actuator, frequency stabilization

14. Roadmap 2009 1011121314151617181920212223242526272829 Mission Objectives Test of key technologies Detection of GW w/ minimum spec. Test FP cavity between S/C Full GW astronomy Scope 1 S/C 1 arm 3 S/C 1 interferometer 3 S/C, 3 interferometer 3 or 4 units DICIGO Pathfinder  Masaki Ando’s talk on Thursday Pre-DECIGO DECIGO R&D Fabrication R&D Fabrication R&D Fabrication SWIM  Wataru Kokuyama’s poster

15. DECIGO Pathfinder (DPF) Local Sensor Actuator Thruster Single satellite Earth orbit Altitude: 500km Sun synchronous Arm length: 1000 km Arm length: 30 cm

16. JAXA’s Small Science Satellite Series Plan to launch 3 small satellites between 2011 and 2015 –using next-generation solid rocket booster Reduce time and cost by “Standard bus system” –Bus weight : 200kg, Bus power : 800W –3-axes attitude control –SpaceWire-based data processing system

17. DECIGO Pathfinder Stabilized. Laser source Interferometer module Satellite Bus system Solar Paddle Mission Thruster head On-board Computer Bus thruster Satellite Bus (‘Standard bus’ system) DPF Payload Size : 950mm cube Weight : 150kg Power : 130W Data Rate: 800kbps Mission thruster x12 Power Supply SpW Comm. Size : 950x950x1100mm Weight : 200kg SAP : 960W Battery: 50AH Downlink : 2Mpbs DR: 1GByte 3N Thrusters x 4

18. DPF Payload Fabry-Perot interferometer Finesse : 100 Length : 30cm Test mass : ~1kg Signal extraction by PDH Drag-free control Local sensor signal  Feedback to thrusters Mission weight : ~150kg Mission space : ~95 x 95 x 90 cm Laser source Yb:YAG laser (1030nm) Power : 25mW Freq. stab. by Iodine abs. line Thruster

19. Goal sensitivity of DPF

20. Detection range

21. Gravity of the Earth Measure gravity field of the Earth from Satellite Orbits, and gravity-gradiometer Determine global gravity field  Density distribution Monitor of change in time Ground water motion Strains in crusts by earthquakes and volcanoes GPS satellite By Araya and Fukuda Observation Gap between GRACE and GRACE-FO (2012-16)  DPF contribution in international network  Ayaka Shoda’s poster

22. R&D for Subsystems  Shuichi Sato’s talk on Thursday, Yuta Michimura’s talk on Thursday Frequency-stabilized laser ThrusterInterferometric sensor Drag-free model Electrostatic sensor/ actuator Test mass module

23. Funding Status Advanced to the final hearing as one of the two candidates for the 2nd small science satellite mission, but not selected. We will apply for the 3rd mission in 2011 (sometime after April).

24. SWIM Tiny GW detector module Launched in Jan. 23, 2009 Test mass Photo sensor Coil TAM: Torsion Antenna Module with free-falling test mass (Size : 80mm cube, Weight : ~500g) Reflective-type optical displacement sensor Separation to mass ~1mm Sensitivity ~ 10 -9 m/Hz 1/2 6 PSs to monitor mass motion ~47g Aluminum, Surface polished Small magnets for position control Photo ： JAXA In-orbit operation

25. Pre-DECIGO DECIGO Arm length100 km1000 km Mirror diameter30 cm1 m Laser wavelength 0.532  m Finesse3010 Laser power1 W10 W Mirror mass30 kg100 kg # of interferometers in each cluster 13 # of clusters14

26. Sensitivity of Pre-DECIGO S/N~14 for NS-NS@300Mpc, 10-20 events/year

27. Pre-DECIGO Science goal of Pre-DECIGO should be defined (with peter Bender’s suggestion: formation of galaxies) –Lead by Shuichi Sato Optimize the design of Pre-DECIGO both for the science goal and technology goal

28. DECIGO Interim Organization PI: Kawamura (NAOJ) Deputy: Ando (Kyoto) Pre-DECIGO Sato (Hosei) Spacecraft Funaki (JAXA/ISAS) Science & Data Tanaka (Kyoto) Seto (Kyoto) Kanda (Osaka City) DECIGO Pathfinder Leader: Ando (Kyoto) Detector A. Ueda (NAOJ) Housing Sato (Hosei) Laser K. Ueda (E.C.) Musha (E.C.) Drag-free Moriwaki (Tokyo) Sakai (JAXA/ISAS) Thruster Funaki (JAXA/ISAS) Bus Takashima (JAXA/ISAS) Data Kanda (Osaka City) Detector Akutsu (NAOJ) Numata (Maryland) Mission Phase Design Phase Executive Committee Kawamura (NAOJ), Ando (Kyoto), Seto (kyoto), Nakamura (Kyoto),Tsubono (Tokyo), Sato (Hosei), Tanaka (Kyoto), Funaki (JAXA/ISAS),Numata (Maryland), Kanda (Osaka City), Ioka (KEK), Takashima (JAXA/ISAS), Yokoyama (Tokyo)

29. 1st International LISA-DECIGO Workshop Nov. 12-13, 2008 @ ISAS, Sagamihara, Japan Participants: –Danzmann, Heinzel, Gianolio, Jennrich, Lobo, McNamara, Mueller, Prince, Stebbins, Sun, Vitale, … Accomplishments: –Mutual understanding –Exposure of the missions to people in the neighboring fields We are grateful for the strong support from the LISA community

30. Collaboration with Stanford MOU for the collaboration –UV LED discharge for DPF/DECIGO –Other R&D for DECIGO We appreciate the great help from the Stanford team (Ke-Xun Sun, Bob Byer, Dan DeBra, …)

31. Other Collaborations JAXA formation flight group –Formation flight Big bang center of the Univ. of Tokyo –DECIGO adopted as one of the main themes Advanced technology center of NAOJ –Discussing the possibility of its becoming the nucleus of DPF NASA Goddard –Fiber laser ⇒ started discussion UNISEC (University Space Engineering Consortium) –Started discussion

32. DECIGO will bring us a variety of fruitful science. The first step to realize DECIGO is to have DPF approved! Conclusions