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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.

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Presentation on theme: "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."— Presentation transcript:

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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


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