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Article
Anomalously porous boulders on (162173) Ryugu as primordial materials from its parent body
Planetesimals—the initial stage of the planetary formation process—are considered to be initially very porous aggregates of dusts1,2, and subsequent thermal and compaction processes reduce their porosity3. The Ha...
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Article
Thermally altered subsurface material of asteroid (162173) Ryugu
Analyses of meteorites and theoretical models indicate that some carbonaceous near-Earth asteroids may have been thermally altered due to radiative heating during close approaches to the Sun1–3. However, the lack...
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Article
Collisional history of Ryugu’s parent body from bright surface boulders
The asteroid (162173) Ryugu and other rubble-pile asteroids are likely re-accumulated fragments of much larger parent bodies that were disrupted by impacts. However, the collisional and orbital pathways from t...
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Chapter and Conference Paper
The X-Ray Spectrum and Variability of NGC 4151
We report investigation of the iron Kα line in a long (100 ks) ASCA observation of NGC 4151. This observation offers unprecedented good statistics; however, the situation is complicated by the fact that the absor...
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Chapter and Conference Paper
X-Ray Properties of High-Z Radio-Quiet Quasars: ASCA Observations
The first-ever high energy (∼ 1–30 keV) X-ray spectra of three z ∼ 2 radio-quiet quasars (RQQs) are presented. If confirmed, the most interesting result is the marginal, but consistent, evidence for FeKaemission ...
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Chapter and Conference Paper
The ASCA Observation Campaign of SS433
Here we present a very short review of the ASCA observation campaign of the enigmatic galactic jet system SS433. The campaign started in 1994 just after the launch, and ended in 1996. Various phases of the 162...
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Article
Theoretical modeling of radiation-driven plasma turbulence in an unmagnetized plasma
The radiation-driven plasma-turbulence problem is in essence an application problem of electrodynamics. In electrodynamics, electromagnetic fields at any point are determined by all charges and currents in the.....
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Article
Wide field X-ray monitor on board the High Energy Transient Experiment (HETE)
The High-Energy Transient Experiment (HETE) is designed for the multiwavelengths study of Gamma-Ray Bursts (GRBs) in UV, X-ray and gamma-ray range with three scientific instruments. The X-ray instrument, Wide-...
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Chapter and Conference Paper
Imaging Design of the Wide Field X-Ray Monitor Onboard the HETE Satellite
The High-Energy Transient Experiment (HETE), to be launched in 1995, will study Gamma-Ray Bursts in an unprecendented wide wavelength range from Gamma-and X-ray to UV wavelengths. The X-ray range (2 to 25 keV)...
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Article
Variability in Active Galactic Nuclei
AGN (Active Galactic Nuclei) have their profound time variability over a wide range of time scales. Although many results of AGN variability have been provided from wide band wavelength observations, I would l...
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Chapter
Variability in Active Galactic Nuclei
AGN (Active Galactic Nuclei) have their profound time variability over a wide range of time scales. Although many results of AGN variability have been provided from wide band wavelength observations, I would l...
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Article
X-ray spectral signatures of very thick cold matter in the Spectra of seyfert galaxies
Over the last few years, GINGA observations of several bright Seyfert galaxies have revealed the existence of a new flat component in the X-ray spectrum of these objects above 8 keV. This component (the «high-ene...
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Article
High-energy spectral changes in three Seyfert galaxies observed with GINGA
We have analysed observations of the three Seyfert Galaxies IC4329A, MCG-6-30-15 and NGC 4051 extracted from the GINGA archive. The variations in the (4⋎18) keV spectrum of the three sources can be interpreted...
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Article
Generation of broadband squeezed states pumped by CW mode-locked pulses
Broadband high level squeezing was clearly observed from 100 kHz to 80 MHz using crystals Ba2NaNb5O15 of 5 mm length, MgO:LiNbO3 of 19 mm length and KNbO3 of 5.8 mm length. Maximum noise reductions detected on a ...
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Chapter and Conference Paper
The iron lines of SS433
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Chapter and Conference Paper
X-ray spectral changes in rapidly variable Seyfert galaxies
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Chapter and Conference Paper
An X-Ray All Sky Monitor for a Japanese Experimental Module on the Space Station
We propose an X-ray all sky monitor for Japanese Experimental Module (JEM) on the space station. Considering practical circumstances, we show as a case study that the all sky monitor with slit hole cameras is ...
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Chapter and Conference Paper
Picosecond Universal Optical Fluctuation in Strongly Disordered Solids
Propagation and scattering of a coherent wave in disordered media show inherently noise-like behavior due to random interference among multitudinously scattered waves [1]. The optical speckle and the universal...
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Chapter and Conference Paper
CCD Camera for the 60cm Telescope at Kagoshima Space Center
A CCD detector has been developed for photometry and image detection with the 60cm reflector at Kagoshima Space Center. The structure and the manipulation of the instrument were simpified by the use of Peltier...
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Article
Coordinated optical-EXOSAT-tenma observations of a burst from 2S1636-536
During a coordinated observations of 2S1636-536 with EXOSAT, Tenma and the 1.4 metre Danish telescope at La Silla, a single burst was detected at all three observatories. The burst was bright with a peak flux ...
