2. High Energy Astrophysics in Japan Makishima Kazuo (Univ. Tokyo / RIKEN) 牧島 一夫 ( 東京大学 / 理化学研究所 ) 島 = tou, shima ; 漢音, 日本音 汽車 自動車 火車 汽車

3. Prof. Oda ’ s group (1975) R.Giacconi (Nobel Prize 2002 ） Minoru Oda 小田稔 (1923 〜 2001) In 1962, a sounding rocket detected strong X-rays from some celestial object, which later turned out to be the brightest cosmic X-ray source, Scorpius X-1.

4. 宇宙科学研究所 (ISAS) 東京大学理学部 (U. Tokyo) 助手 (R.Associate) 助教授 Assoc. Prof.) 教授 (Prof.) 宇宙 X 線 Cosmic X-rays 太陽 X 線 Solar X-rays Yohko HXT ASTRO-E HXD ASRO-E Launch failuire Ginga LAC Hakucho ASCA GIS SPC battery Tenma 1980 1982 1984 1986 1988 1990 199219941996 1998 2000 2002 RIKE N ASTRO- E2 HXD SXT Data recorder Hinotori battery My Participation to Satellite Projects

5. Prologue: Ohsumi 大隅 On 1970 February 11, the Institute of Space and Astro-nautical Science (ISAS ；宇宙科学研究所 ) successfully launched the first Japanese artificial satellite, Ohsumi. This was achieved after 4 launch failures. 重量 Weight ： 24 kg 軌道 Orbit ： 近地点 Perigee 350 km 遠地点 Apogee 5140 km 軌道傾斜角 Inclinaton 31deg

6. 科学衛星（宇宙科学研究 所） L- ４ S M-4S M-3C M-3H M-3S M-3SI I M-5 淡青, 新星, 電波 Ohsumi 淡青２, 太陽, CORSA, 白鳥 淡青３, 極光, 磁気圏 淡青４, 火鳥, 天馬, 大空 Sakigake, 彗星, 銀河, 曙, 飛天, 陽光, ASCA HALCA, Nozomi, ASTRO-E, Hayabusa 1970’s Former 80 ’ s Latter 80 ’ s 〜 Former 90 ’ s Geophysics Solar Physics Astrophysics Planetary

7. 衛星 ３段 ２段 1段1段 How a 3-Stage Rocket Works 1段1段 ３段 Kick motor (optional) ２段

8. 1. Hakucho 白鳥 重量 Weight ： 96 kg 軌道 Orbit ： 近地点 Perigee 545 km 遠地点 Apogee 577 km 傾斜角 Inclination 30 deg [E] Elementary process 素過程 [A] Astrophysics 天体物理 [I] Instrumentation 観測装置 [S] Spacecraft Technology 衛星技術 The first Japanese cosmic X-ray satellite, launched on 1979 February 21. Re-entered atmosphere on 1985 April 16. This was a recovery mission to the CORSA satellite, which had been lost in 1976 due to a rocket failure.

9. [S] Attidue ( 姿勢 ) of Hakucho MxMx MzMz MyMy  Attitude of Hakucho was stabilized by a free spin with a period of 〜 10 sec.  Attitude maneouvering was done by activating 3 electric magnets, and utilizing the magnetic torque between the geomagnetic field.  Detectors mounted on the top face performed pointing observations, while those on the sides scanned over the sky. Local mag.field

10. High Voltage  Simple, cheap, large-area  Suited to 2 〜 20 keV  ΔE/E 〜 15% @ 6 keV  Pulse Height ∝ E ×V α (α 〜 6) A photoelectron Electron multiplication Charge cloud An X-ray Thin wire anode Collimator and Window support Pre-amplifier Very thin Metal window Main Electronics Hermetic Insulator Gas outlet Gas inlet Ar+CH 4 (10%) [I] Proportional Counters ( 比例計数管 ) Metal box or tube pulse

11. [E] Blackbody Radiation ( 黒体放射 ) ◆ Photon number spectra 0.1 1 10 E (keV) 100 10 1 0.1 0.01 photons/sec/keV f ∝ E×kT Peak at E 〜 2 kT kT = 1 keV kT = 3 keV kT =0. 3 keV f ph =A E 2 /{1-exp(E/kT)}  Total emitted luminosity L = 4πR 2 σT 4  Theory predicts that a neutron star has a radius of R 〜 10 km, and its luminosity saturates at the Eddington limit of 2×10 38 erg/s. We then expect T = 2.0 keV.  If T and L are measured, we can estimate R from observation. ◆ Planck ’ s formula ◆ Stefan-Boltzmann ’ s law

12. Flux R 15 sec Blackbody kT [A] Scientific Highlights from Hakucho  Using rotation modulation collimators, w observed many X-ray bursts (thermo-nuclear flash on the NS surface).  Confirmed R 〜 10 km ( Ohashi et al. ApJ 254, 254, 1982).  Assuming burst luminosity = Eddington limit, the Galactic Center distance should be 〜 7 kpc rather than 10 kpc (Inoue et al. ApJ 250, L71,1981). 2.0 keV 10 km

13. 2. Hinotori 火の鳥  The first Japanese solar X-ray satellite, lunched in 1981 February, aiming at a solar maximum.  Using rotating modulation collimators coupled to NaI scintillation counters, it successfully resolved hard X-ray images of solar flares witn ~30 ” resolution.  Mission ended in 2 years due to a trouble in the data recorder. 重量 Weight ： 188 kg 軌道 Orbit ： 近地点 Perigee 576 km 遠地点 Apogee 644 km 傾斜角 Inclination 31 deg

14. [I] How a Scintillation Counter Works  Simple, cheap  Suited to 20 〜 600 keV  ΔE/E 〜 20% @ 100 keV  Pulse Height ∝ E ×V α (α 〜 7) High Voltage Bleeder Main Electronics An X-ray Pre-amplifier Magnetic shield Photo- Multiplier tube Light guide NaI crystal Visible-light shield Scintillation pulse

15. [A] Scientific Highlights from Hinotori A gradual rim flare of 1981 April 27 ( Takakura et al. ApJ 270, L83, 1983) 17-40 keV hard X- ray image at the flare peak 40-67 keV 17-40 keV 67-150 keV 150-350 keV 2 arcmin 10 min Hard X-ray emission from loop footpoints, and also from loop top? Solar disk

16. [E] Non Thermal Bremsstrahlung ( 非熱的制動放射 ) Relativistic electrons Collision with ions Collision with e - 0.1 1 10 E (MeV) 0.1 1 10 E (MeV) Softer e ’ s are subject to larger Coulomb loess For a mono-energetic electron dsitribution photon flux ∝ 1/E Coulomb scatt. --- elastic, but large momentum transfer Bremsstrahlung -- hard X-rays Coulomb scatt. --- inelastic, also momentum changes Negligible Bremsstrahlung Convolved with power-law electron distribution

17. [E] Optically-Thin Thermal Plasma Emission Optically-thin hot plasmas (e.g., solar corona) become strong X-ray sources. Then, how does their emission differ from the blackbody (optically thick emission) ?  L = n 2 V Λ(T,Z) ∝ volume ( 体 積 ), rather than surface area ( 表面積 ), bacause the source is transparent.  Continuum stronger at lower energies, due to the absence of self-absorption: f ph =A E -1.4 exp(-E/kT)  Accompanied by strong atomic emission lines. 0.1 1 10 E (keV) 100 10 1 0.1 0.01 photons/sec/keV both kT = 1 keV Thin- thermal Black body

18. [S] Orbit ( 軌道 ) of Hinotori Near-Earth X-ray satellites must have altitudes between 500 〜 600 km.  If ＜ 500 km ⇒ Air drag shortens the satellite lifetime.  If ＞ 600 km ⇒ Particle background increases due to the radiation belt In such an orbit, a satellite makes 15 revolutions per day (period of 〜 95 min).  From a tracking station in Japan, we can have only 5 “ contacts ” per day, each 〜 10 minutes.  Utilizing these 50 minutes, all commands must be sent to the satellite, and all data stored onboard must be received. 1 35 9 13 After operating for 〜 2 years, Hinotori lost proper functioning of its data recorder (a tape reccordder).

19. 3. Tenma 天馬  The 2nd Japanese cosmic X-ray satellite, launched on 1983 February 20. It operated over the same era as the European EXOSAT.  It carried onboard the Gas Scintillation Proportional Counter (SPC) with a factor 2 better energy resolution than conventional proportional counters.  It has initiated a number of important spectroscopic studies, including the Fe-K diagnostics, although targets were mostly limited to Galactic objects.  Mission ended in 1.5 years due to a battery explosion. 重量 Weight ： 216 kg 軌道 Orbit ： 近地点 Perigee 497 km 遠地点 Apogee 503 km 傾斜角 Incl. 32deg 重量： 216 kg 軌道： 近地点 497 km 遠地点 503 km 軌道傾斜角 32 deg Tanaka et al. PASJ 36, 641 (1984)

20. [I] How to Improve the Energy Resolution? Accelerated in a parallel E-field, each electron emits many UV photons Amplified by photo- multiplier Accelerated in a cylindrical E-field, e ‘ s are multiplied sequentially Additional fluctuation ◆ Proportional Counter ◆ Gas Scintil- lation P.C. （ Tenma SPC, ASCA GIS) ◆ Solid State Detector No signal amplification Numerous e-h pairs Low-noise amplifier Electrical noise X-ray Primary e ’ s with fluctuation Little fluctuation

21. [A] Scientific Highlights from Tenma (1) Koyama et al. ApJ 38, 121 (1986) Tsunemi et al. ApJ 306, 248 (1986) From various cosmic hot plasmas, Tenma detected ionized (mainly He-like) Fe-K lines at 〜 6.7 keV. These lines confirmed thermal process in these objects; provided information on the plasma temperature and Fe abundance; and allowed us to examine the plasma for ionization (non-) equilibrium. Okumura et al. PASJ 40, 639 (1988) 銀河団 Perseus cluster Fe/H 〜 0.3 solar 銀河面Ｘ線放射 Galactic ridge X-ray emission Hot plasmas fill the interstellar space! 超新星残骸 Cas A Ionization non- equilibrium convirmed!

22. [A] Scientific Highlights from Tenma (2) Fluorescent K-lines of neutral Fe was also detected at 6.4 keV from various objects. The lines provide a valuable diagnostic tool of cold matter distribution around the X-ray sources. Nagase et al. PASJ 38, 547 (1986) The binary X-ray pulsar (a mass accreting magnetic NS), Vela X-1 Matusoka et al. PASJ 38, 285 (1986) The Seyfert galaxy NGC4151 out of eclipse near eclipse instrumental

23. [A] Scientific Highlights from Tenma (3)  Mitsuda et al. (PASJ 36, 741, 1984) successfully decomposed spectra of low-mass NS binaries into emission from a standard accretion disk (diskBB model), and a blackbody from the NS surface.  The same MCD model can successfully describe high-state spectra of the BH candidate GX339-4. The disk inner radius is constant, at 〜 3 R s (Makishima et al. ApJ 308, 635,1986). diskBB model 1 week 30 20 10 0 Disk inner radius (km) diskBB blackbody

24. [S] Electric Power of a Satellite Solar cells 太陽電池 shunt Spacecraft and instruments ◆ Satellite Day 昼 ( 〜 60min) ◆ Satellite Night 夜 ( 〜 30min) NiCd battery ２次電池 time Bat V 電圧 shunt Spacecraft and instruments NiCd battery ２次電池 death !!! ~1.2V/cell ~1. 6V/cell !!! (charge) (discharge)

25. 4. Ginga 銀河  The 3rd cosmic X-ray satellite of Japan, launched on 1987 February 5 and re-entered on1991 Novemer 1.  It carried onboard the Large Area Proportional Counter (LAC), developed under an extensive UK-Japan collaboration.  It had an improved spacecraft performance, e.g., 3-axis stabilization, CPU-based attitude control, etc.  It opened a full window in the 2-30 keV range to extra-galactic X-ray sources, including SN1987A. 重量 Weight ： 420 kg 近地点 Perigee: 530 km 遠地点 Apogee: 670 km Turner et al. PASJ 41, 345(1989)

26. [I] Background Reduction using MWPC ◆ MPWC = Multi-Wire Proportional Counter ( 多芯比例計数管） HEAO-1 A2, EXOSAT ME, Ginga LAC, RXTE PCA R1L1 V2 V1S23 A schematic cross section of the Ginga LAC detector (Turner et al. Publ. Asttr. Soc. Japan 41, 345, 1989)

27. [S] Three-Axis Stabilization (3 軸制御 ) A B C D x y z  A 〜 D all spin up ⇒ satellite rotates around Z-axis Angular momentum is carried by four fast-spinning bias momentum wheels, while the satellite body is at rest. Three wheels are sufficient, but the 4th one is installed for redundancy.  A&B spin up, C&D spin down ⇒ around x-axis  A&D spin up, B&C spin down ⇒ around y-axis

28. The highly sensitive Ginga detected X- rays from neaby normal galaxies. The emission from M31 (Andromeda) is dominated by LMXBs (Makishima et al. PASJ 41, 697, 1989). [A] Scientific Highlights from Ginga (1) TheM31 spectrum 〜 that o a Galactic LMXB, 4U1820-30. The diskBB+BB model can explain the M31 spectrum above 〜 2 keV.

29. [E] Photoelectric Absorption of X-rays 10 -22 10 -20 σ[cm -2 /H] 10 -24 0.1 1 10 E (keV) 10 1 0.1 Wilms, Allen and McCray ; ApJ 542, 914-924 (2000) ◆ Interstellar photoelectric absorption cross sectoin ◆ Absorbed spectra N H ＜ 10 20 σ ∝ E -2.5 C O Ne Mg Si S Fe 10 23 10 24 N H =10 22 N H =10 21

30.  Highly absorbed spectra have been detected from a number of Type II Seyfert galaxies (e.g., Awaki et al. PASJ 43, 195, 1991).  Type II objects show systematically stronger Fe- K lines than Type I ’ s.  These results support the “ unified scheme ” of AGNs; Type I are viewed pole-on, while Type II edge-on. [A] Scientific Highlights from Ginga (2) NGC4570 (Type II) NGC4593 (Type I)

31. 1 2 5 10 20 50 Energy (keV) ◆ A tansient pulsar X0331+53 Makishima et al. ApJ 365, L59 (1990) E r = 28 keV → B = 2.4×10 12 G 0 2 4 6 8 10 Cyclotron Res. Energy (keV) Number 10100 202 550 Log[B/(1+z)] (Gauss) 1213  Ginga detected elecctron cyclotron absorption lines from a dozen binary X-ray pulsars (Makishima et al. ApJ 525, 978,1999).  The measured surface magnetic fields are tightly clustered over (1- 4)×10 12 G, arugueing against the magnetic field decay hypothess. [A] Scientific Highlights from Ginga (3) SAX Ginga RXTE ASTRO-E2 HXD ASC A

32.  After Hinotori, the second Japanese solar observatory Yohkoh was launched on 1991 August 30.  It kept observing the sun for a full solar cycle.  In december 2001, however, Yohkoh received an attitude disturbance during a solar eclipse, and the NiCd battery became empty. This caused the mission termination. 5. Yohkoh 陽光 重さ Weight ： 395 kg 近地点 Perigee : 〜 500 km 遠地点 Apogee : 〜 800 km Ogawara et al. PASJ 44, L41 (1992)

33.  Tow imagers:  Soft X-ray Telescope: Using a high-resolution mirror and the first space-use X-ray CCD, it took millions of coronal pictures, and innovated the solar physics.  Hard X-ray Telescope: Employing modulation collimators in “ Fourier-synthesis ” configuration, it succeeded in the high- resolution (~5 ” ) imaging of more than 1000 solar flares in the 15-95 keV hard X-rays. Particle acceleration is being studied.  Two spectrometers:  The Bragg Crystal Spectrometer: High energy-resolution diagnostics of detailed plasma motion.  The Wide Band Spectrometer: from 〜 1 keV to ~30 MeV. [I] Instruments onboard Yohkoh

34. [E,I] How to Reflect and Focus X-rays ? Visible light 可視光 X-ray ◆ Total reflection 全反射 n < 1 refractive index （屈折率 ) n > 1 Parabolloid 回転放物面 Optical axis 光軸 Focal plane 焦点面 ◆ Paraboloid collector Paraboloid 回転放物面 Hyperboloid 回転双曲面 ◆ Wolter Type I Optics

35. Actuators Magnetic torquers Momentum wheels Gas jets … [S] Closed-loop Attitude Control ( 姿勢制御） Attitude Sensors Star tarckers Sun sensors Horizon sensors Gyroscopes … Dynamical response of the satellite 比較 Target attitude Automated Attitude Calclation Error signal

36. 宇宙科学研 http://www.isas.ac.jp Long-term variation of the coronal activity  Solar flares are powered by magnetic reconnection!  Solar corona is probably heated by reconnection through numerous micro-flares.  However, the basic puzzle still remains: why there should be a 5 million K corona above the 6000 K photosphere? [A] Highlights of the Soft X-ray Telescope X-ray colona

37. [A] Highlights of the Hard X-ray Telescope 36 100 1000 200 0 0 0 0 0 0 40 80 2000 6000 600 0.5 秒ごとの 53-93 keV 画像 １ minutes 53-93 keV 6.2-8.8 MeV 0.22-1.4 MeV 10-30 MeV 1998 August 18, UT 22h 16m 15-23 keV 33-53 keV 0.5 秒ごとの 53-93 keV 画像 14-23 keV 33-53 keV Solar rim 30arcsec  The largest gamma-ray flare ever detected with Yohkoh  Evidence of gamma-ray emission from loop-top regions  Particles are accelerated at the loop top?

38. [A] A Possible Scenario of Acceleration Magnetic field line Main acceleratin regoin Reconnection point photosphere Hardest, impulsive gamma-rays Softer, gradual gamma-rays Hard X-rays Cool plasma stream Accelerated electrons

39. 6.ASCA 飛鳥 Advanced Satellite for Cosmology and Astrophysics 重量 Weight ： 417 kg 近地点 Perigee: 520 km 遠地点 Apogee: 620 km  Developed under a Japan-US collaboration, and launched on 1993 February 20 (10 years since Tenma). It carried high-throughput mirrors working up to 10 keV, coupled to the SIS (CCD camera) and the Japanese GIS (imaging GSPC).  ASCA produced a revolution in the cosmic X-ray study.  ASCA lost the attitude stability on 2001 July 14 due to a big solar flare, and re-entered on 2001 March 2. Tanaka et al., PASJ 46, L37(1994)

40. [S] Radiative Cooling of Instruments Instruments such as CCDs may be cooled to 〜 100 ℃ by using thermoelectric cooler (TEC), heat pipe, and radiator panels. CCD TEC Heat sink Heat pipe sunshade Radaitor panel Plastic (high far-IR emissivity) Silver or Alminium (low near-IR absorptivity)

41. [I] What are required for X-ray CCDs? In the flux-accumulation mode (e.g. Yohkoh SXT)  The front protective layer as thin as possible, to increase the soft X-ray transmission.  The depletion layer as thick as possible, to increase the hard X-ray stopping power. In the single-photon detection mode (e.g. ASCA SIS, Chandra ACIS, XMM-Newton EPIC), in additon  A very high charge-transfer efficiency, to ensure a good energy resolution (ΔE/E 〜 2%@ 6 keV).  Low-noise readout electronics to retain good energy resolution  A fast clocking to avoid photon pile-up.

42. [E] Dual Scientific Merits of ASCA (1) Superior energy resolution (with particularly the SIS) (2) Hard X-ray imaging in energies above 〜 2 keV (particularly non-thermal emission with the GIS) Dual Doppler-shifted atomic lines from SS433 (Kotani et al. PASJ 46, L147, 1994 ) Gyration around magnetic fields Collision with soft photons, particularly of the CMB Relativistic electrons with Lorentz factor γ Synchrotron radiation at ν 〜 10 6 B[μG]γ 2 Hz Inverse Compton emission at ν 〜 ν soft γ 2

43. [A] Individual Talks from Japan  Non-thermal X-rays Makoto Tashiro （田代 信） [Sept. 21, 16:50]  Thermal X-rays from clusters of galaxies Isao Takahashi （高橋 勲） [Sept.22, 9:15]  Diffuse emission from spiral galaxies Hiromitsu Takahashi （高橋弘充） [Sept.22,14:40]  Black hole binaries and ULXs Aya Kubota （久保田あや） [Sept.22,17:25]  AGNs, particularly those of low luminosities Yuichi Tearshima （寺島雄一） [Sept.22,18:15]  Gamma-ray bursts Toru Tamagwa （玉川 徹） [Sept.24, 8:30]

44.  On 2000 February 10, we failed to put the 5th X-ray satellite ASTRO-E in orbit, due to a rocket trouble. The Hard X-ray Detector (HXD), aiming at the highest sensitivity in the 10-600 keV range, was also lost.  However, we have been given another chance, and will launch ASTRO-E2 in January 2005.  We are busy integrating the HXD-II. Epilogue