1. Sora GWADW @Elba, Italy May 15, 2008 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

2. Fortune Cookie July 2007, Amaldi 7 @ Sydney

3. We gained momentum! DPF was selected as one of five important mission candidates for small science satellite series run by JAXA/ISAS

4. 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 10 4 10 2 10 0 10 -2 Frequency [Hz] Strain [Hz -1/2 ] LISA DECIGO Terrestrial detectors (e.g. LCGT) Confusion Noise moved above LISA band To be moved into TD 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 (e.g. LISA) Shot noise Shorten arm length Shot noise f 1 Radiation pressure noise f -2 Transponder type (e.g. LISA) Shorten arm length Implement FP cavity FP cavity type Better best- sensitivity

7. Drag free and FP cavity: compatible? Mirror S/C I S/C II

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

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

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

11. Inflation 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 unit

12. 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.

13. Roadmap 200708091011121314151617181920212223242526 Mission Objectives Test of key technologiesDetection 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 (DPF) Pre-DECIGO DECIGO R&D Fabrication R&D Fabrication R&D Fabrication

14. Pre-conceptual design and objectives of DPF Thruster Local Sensor Floating mirror Rigid Cavity 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

15. Goal sensitivity of DPF

16. Expected sources

17. Stabilized laser Interferometer Thruster control Bus Solar puddle Interferometer control Housing control Thruster head Central operator Bus thruster Schematic view of DPF

18. DPF Solar Synchronous polar orbid Altitude: 500km, Period: 100 min 500km Orbit of DPF

19. Interim organization PI: Kawamura (NAOJ) Deputy: Ando (Tokyo) Executive Committee Kawamura (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 pathfinder Leader: 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

20. Current status There are now 140 members from 50 institutes in DECIGO working group DPF was selected as one of five important mission candidates for small science satellite series run by JAXA/ISAS; a budget for R&D was allocated At the end of 2008, the 2 nd and 3 rd missions will be selected. (1 st mission already selected)

21. Let DPF fly!