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The Gamma-ray Large Area Space telescope (GLAST) is a gamma-ray satellite scheduled for launch in 2008. Before the assembly of the Tracker subsystem of the Large Area Telescope (LAT) science instrument of GLAST, every component (tray) and module (tower) has been subjected to extensive ground testing required to ensure successful launch and on-orbit operation. This paper describes the sequence and results of the environmental tests performed on an engineering model and all the flight hardware of the GLAST LAT Tracker. Environmental tests include vibration testing, thermal cycles and thermal-vacuum cycles of every tray and tower as well as the verification of their electrical performance.

著者人数: 61名, Accepted: 2007-08-22, 資料番号: SA1000711000

A unique electronics system has been built and tested for reading signals from the silicon-strip detectors of the Gamma-ray Large Area Space Telescope mission. The system amplifies and processes signals from 884 736 36-cm long silicon strips in a 4times4 array of tower modules. An aggressive mechanical design fits the readout electronics in narrow spaces between the tower modules, to minimize dead area. This design and the resulting departures from conventional electronics packaging led to several fabrication challenges and lessons learned. This paper describes the fabrication processes and how the problems peculiar to this design were overcome

We present a multiwavelength study of the field containing the unidentified X-ray source AX J1639.0-4642, discovered with the ASCA observatory and recently detected with the IBIS telescope, onboard the INTEGRAL satellite, dubbed IGR J16393-4643. The huge hydrogen column density towards the source, the hard spectral index in the 0.7-10 keV band and its flux variability suggest that the source is a High Mass X-ray Binary (HMXB) enshrouded by dust. Our search reveals the presence of a non-thermal radio counterpart within the X-ray error box. After a study of the broadband emission from X-rays to the radio domain, we propose that AX J1639.0-4642 is a dust-enshrouded Microquasar (MQ) candidate. In addition, the X-ray source is well within the 95% location contour of the unidentified gamma-ray source 3EG J1639-4702. The main properties of AX J1639.0-4642/3EG J1639-4702 are consistent with those of two other MQs previously proposed to display high-energy gamma-ray emission., Comment: 7 pages, 5 figures. Accepted for publication in A&A. Title and discussion on the possible NIR counterpart have been modified

Gamma-ray large area space telescope (GLAST) is a next generation high-energy gamma-ray space observatory designed for observations of celestial gamma-ray sources in the energy band extending from 10 MeV to more than 100 GeV. The main instrument, the large area telescope (LAT), consists of a microstrip silicon tracker, a calorimeter, an anticoincidence detector, and the data acquisition (DAQ) system. This paper summarizes the results obtained during the radiation testing of the ASIC chips used in the LAT tracker. Both single event effects (SEE) and total ionizing dose effect (TID) tests have been performed, as part of the radiation hardness assurance (RHA) for the planned 5-yr mission. Heavy-ion SEE tests have been performed at the SIRAD irradiation facility at the INFN National Laboratories of Legnaro, Italy (LNL) and at the Texas A&M University (TAMU) Cyclotron Institute, with LET values ranging up to /spl sim/80 MeV/spl times/cm/sup 2//mg. The tolerance of the chips to ionizing radiation has been evaluated with heavy ions and by irradiating chips with the spherical /sup 60/Co gamma source of the LNL CNR-ISOF laboratory.

著者人数：36名, 資料番号: SA1002239000

著者人数：33名, 資料番号: SA1001500000

We report here the discovery of a new X-ray pulsator, AX J170006-4157, in the Galactic plane. The source was observed three times between 1994 and 1997 by the Advanced Satellite for Cosmology and Astrophysics. Significant pulsations with P = 714.5 ? 0.3 s were discovered from the third observation made between MJD 50,707.8926 and MJD 50,710.2199. The X-ray spectrum is described by a flat power-law function with a photon index of 0.7. Although the spectrum could also be fitted by thermal models, the temperature obtained was unphysically high. The hard spectrum suggests that the source is a neutron star binary pulsar similar to X Persei (4U 0352+309), but we cannot completely exclude the possibility that it is a white dwarf binary.

著者人数：14名, Accepted: 1997-10-10, 資料番号: SA1001912000

Massive black holes are believed to reside at the centres of most galaxies. They can be- come detectable by accretion of matter, either continuously from a large gas reservoir or impulsively from the tidal disruption of a passing star, and conversion of the gravitational energy of the infalling matter to light. Continuous accretion drives Active Galactic Nuclei (AGN), which are known to be variable but have never been observed to turn on or off. Tidal disruption of stars by dormant massive black holes has been inferred indirectly but the on- set of a tidal disruption event has never been observed. Here we report the first discovery of the onset of a relativistic accretion-powered jet in the new extragalactic transient, Swift J164449.3+573451. The behaviour of this new source differs from both theoretical models of tidal disruption events and observations of the jet-dominated AGN known as blazars. These differences may stem from transient effects associated with the onset of a powerful jet. Such an event in the massive black hole at the centre of our Milky Way galaxy could strongly ionize the upper atmosphere of the Earth, if beamed towards us.

Several mechanisms have been proposed to contribute to cardiac dysfunction in obesity models, such as alterations in calcium (Ca²⁺) handling proteins and β-adrenergic receptors. Nevertheless, the role of these factors in the development of myocardial dysfunction induced by obesity is still not clear.The purpose of this study was to investigate whether obesity induced by hypercaloric diets results in cardiac dysfunction. Furthermore, it was evaluated whether this functional abnormality in obese rats is related to abnormal Ca²⁺ handling and the β-adrenoceptor system.Male 30-day-old Wistar rats were fed with standard food (C) and a cycle of five hypercaloric diets (Ob) for 15 weeks. Obesity was defined as increases in body fat percentage in rats. Cardiac function was evaluated by isolated analysis of the left ventricle papillary muscle under basal conditions and after inotropic and lusitropic maneuvers.Compared with the control group, the obese rats had increased body fat and glucose intolerance. The muscles of obese rats developed similar baseline data, but the myocardial responsiveness to post-rest contraction stimulus and increased extracellular Ca²⁺ were compromised. There were no changes in cardiac function between groups after β-adrenergic stimulation.Obesity promotes cardiac dysfunction related to changes in intracellular Ca²⁺ handling. This functional damage is probably caused by reduced cardiac sarcoplasmic reticulum Ca²⁺ ATPase (SERCA2) activation via Ca²⁺ calmodulin kinase.

MAXI, the first astronomical payload on JEM-EF of ISS, began operation on August 3, 2009 for monitoring all-sky X-ray images every ISS orbit (92 min). All instruments as well as two main X-ray slit cameras, the GSC and SSC, worked well as expected for one month test operation. The MAXI has been operated since August, 2009 and monitored more than 300 X-ray sources, which include Galactic black holes and black hole candidates (BH/BHC), transient X-ray pulsars, X-ray novae, X-ray bursts, CVns, a considerable number of AGNs and so on. Automatic nova-alert and rapid report system is starting up, while we have published more than 30 results publicly on GCN and ATel with manual analysis. We are also releasing daily data more than 200 targets publicly. Now MAXI has continued steady operation since the beginning of 2010 although capability of a part of X-ray detectors is going down from initial ability. We have obtained some remarkable results concerning BH/BHC, X-ray pulsars and AGNs. As one of the results XTE J1752-223, an X-ray nova accompanying a black hole candidate, has revealed an evolution of accretion disc and high energy plasma from the data for seven-month observations. In this paper we report the operation status of MAXI on the ISS as well as early several astronomical results.

MAXI, the first astronomical payload attached to ISS JEM‐EF, began operation on August 3, 2009 for monitoring all‐sky X‐ray images every ISS orbit (92 min). This paper reports the first results obtained during the 1‐month test observations. All instruments as well as two main X‐ray slit cameras, the GSC and SSC, worked as we expected. The detection limits of MAXI‐GSC are about 25 mCrab and 8 mCrab for one ISS orbit (92 min) and 1‐day observations, respectively. GSC covers about 76% and 96% of the entire sky for respective single‐orbit and 1‐day observations. MAXI has detected a transient X‐ray pulsar A0535+26, an X‐ray burst, and a gamma‐ray burst in the first month of the test observation period.

The Monitor of All‐sky X‐ray Image (MAXI) is the unprecedentedly sensitive all‐sky X‐ray monitor. Gas Slit Camera (GSC) of MAXI is sensitive for 2–30 keV bands and sweeps almost the whole sky once every 90 minutes with long narrow fields of view (FoV). We developed the PSF(Point Spread Function)‐fitting method for the scanning data of MAXI/GSC to calculate the position and flux of X‐ray point sources. This method is useful both to determine the position of a transient source like GRBs and to calculate the fluxes of sources located in a crowded region. For transients whose duration is shorter than one scan (about 30 sec–4 min), other method is applied to determine the position without assumption of constancy of X‐ray flux. The locations of two short X‐ray transients discovered by MAXI/GSC (ATel ♯2321 and ♯2415) were determined by these methods.

MAXI, Monitor of All‐sky X‐ray Image, is the first astronomical telescope onboard the ISS. One of the main goals of our mission is to discover new transient objects by scanning more than 95% of the sky every ∼92 min with two types of X‐ray cameras, Gas Slit Camera (GSC) and Solid‐state Slit Camera (SSC) [1].We have developed a completely new data analysis system, a nova alert system, to find transient objects and send alerts to the world as soon as possible. Here we describe the current status of the system, and transient objects discovered with the system.

We present a 2 - 10 keV ASCA observation of the field around the soft gamma repeater SGR1627-41. A quiescent X-ray source was detected in this observation whose position was consistent both with that of a recently discovered BeppoSAX X-ray source and with the Interplanetary Network localization for this SGR. In 2 - 10 keV X-rays, the spectrum of the X-ray source may be fit equally well by a power law, blackbody, or bremsstrahlung function, with unabsorbed flux ~5 x 10^-12 erg cm^-2 s^-1. We do not confirm a continuation of a fading trend in the flux, and we find no evidence for periodicity, both noted in the earlier BeppoSAXobservations.

The Large Area Telescope (LAT) on--board the Fermi Gamma ray Space Telescope began its on--orbit operations on June 23, 2008. Calibrations, defined in a generic sense, correspond to synchronization of trigger signals, optimization of delays for latching data, determination of detector thresholds, gains and responses, evaluation of the perimeter of the South Atlantic Anomaly (SAA), measurements of live time, of absolute time, and internal and spacecraft boresight alignments. Here we describe on orbit calibration results obtained using known astrophysical sources, galactic cosmic rays, and charge injection into the front-end electronics of each detector. Instrument response functions will be described in a separate publication. This paper demonstrates the stability of calibrations and describes minor changes observed since launch. These results have been used to calibrate the LAT datasets to be publicly released in August 2009., 60 pages, 34 figures, submitted to Astroparticle Physics

The Gamma-ray Large Area Space Telescope represents a great advance in space application of silicon detectors. With a surface of 80 m 2 and about 1 M readout channels it is the largest silicon tracker ever built for a space experiment. GLAST is an astro-particle mission that will study the mostly unexplored, high energy (20 MeV–300 GeV) spectrum coming from active sources or diffused in the Universe. The detector integration and test phase is complete. The full instrument underwent environmental testing and the spacecraft integration phase has just started: the launch is foreseen in late 2007. In the meanwhile the spare modules are being used for instrument calibration and performance verification employing the CERN accelerator complex. A Calibration Unit has been exposed to photon, electron and hadron beams from a few GeV up to 300 GeV. We report on the status of the instrument and on the calibration campaign.

Diets rich in saturated fatty acids are one of the most important causes of atherosclerosis in men, and have been replaced with diets rich in unsaturated fatty acids (UFA) for the prevention of this disorder. However, the effect of UFA on myocardial performance, metabolism and morphology has not been completely characterized. The objective of the present investigation was to evaluate the effects of a UFA-rich diet on cardiac muscle function, oxidative stress, and morphology. Sixty-day-old male Wistar rats were fed a control (N = 8) or a UFA-rich diet (N = 8) for 60 days. Myocardial performance was studied in isolated papillary muscle by isometric and isotonic contractions under basal conditions after calcium chloride (5.2 mM) and ss-adrenergic stimulation with 1.0 microM isoproterenol. Fragments of the left ventricle free wall were used to study oxidative stress and were analyzed by light microscopy, and the myocardial ultrastructure was examined in left ventricle papillary muscle. After 60 days the UFA-rich diet did not change myocardial function. However, it caused high lipid hydroperoxide (176 +/- 5 vs 158 +/- 5, P0.0005) and low catalase (7 +/- 1 vs 9 +/- 1, P0.005) and superoxide-dismutase (18 +/- 2 vs 27 +/- 5, P0.005) levels, and discrete morphological changes in UFA-rich diet hearts such as lipid deposits and mitochondrial membrane alterations compared to control rats. These data show that a UFA-rich diet caused myocardial oxidative stress and mild structural alterations, but did not change mechanical function.

A unique electronics system has been built and tested for reading signals from the silicon-strip detectors of the Gamma-ray Large Area Space Telescope mission. The system amplifies and processes signals from 884 736 36-cm strips using only 160 W of power, and it achieves close to 100% detection efficiency with noise occupancy sufficiently low to allow it to self trigger. The design of the readout system is described, and results are presented from ground-based testing of the completed detector system.

The ASTRO-E Hard X-ray Detector utilized GSO/BGO well-type phoswich counters in compound-eye configuration, to achieve an extremely low background level of a few /spl times/10/sup -5/ counts s/sup -1/ cm/sup -2/ keV/sup -1/. The GSO scintillators installed in the BGO active shield wells observes 30-600 keV photons, while silicon PIN diodes of 2 mm thick placed in front of each GSO crystal covers 10-60 keV photons with energy resolution of /spl sim/3.5 keV FWHM. The design goals both of low background and high energy resolution in the hard X-ray bands were confirmed to be achieved through the preflight calibration experiments.

This paper proposes a new type of heuristic evaluation method, called the structured heuristic evaluation method (or sHEM). This is expected to detect more of the usability problems as compared to the conventional heuristic evaluation method introduced by Nielsen (1993, 1995). Based on the comparative study we report the experimental results on the effectiveness of the method. There is a trade-off between the number of the activated usability heuristics in the evaluator's memory and the number of problems to be detected by him/her. Our proposition is to solve this trade-off by introducing the structure into the set of usability heuristics, i.e. by splitting the evaluation session into several sessions, each of which focuses on only the specific aspect of the whole usability heuristics.

The biggest Internet portal-site in Japan is NTT's "goo" site, www.goo.ne.jp. Its speciality is its ability to handle the Japanese language. It uses the most powerful information search engine for the Japanese language so it provides a comfortable environment for the users who want or who must read Japanese information. Unlike the manually structured directory style of "Yahoo!", the computer-based robot-style search mechanism in "goo" automatically retrieves information from the net. Furthermore, "goo" provides the most up-to-date information through its original service "mogitate goo" which means "freshly-squeezed goo". Information categories such as the news site "Nikkei goo", also work perfectly to help the user find what he is looking for. We describe the key technologies behind the "goo" site and its services. The keys are the "InfoBee" information handling technologies, such as the information retriever, crawler, indexer and Japanese analyzer. The system described doesn't require a high performance super-computer. It works effectively on a workstation-cluster, even a whitebox-based personal computer cluster. It is economical, scalable, and offers the same performance as a super-computer.

We are developing Monitor of All Sky X-ray Image (MAXI) which will be mounted on the Japanese Experiment Module of the International Space Station. MAXI is an all-sky X-ray monitor which scans the sky in every 90 minutes. The sensitivity will be as high as 7 mCrab (5 (sigma) level) in one scan and 1 mCrab in one-week accumulation. The GSC (Gas Slit Camera) instrument consists of twelve one-dimensional position sensitive proportional counters using the Xe++CO2 gas and the carbon fiber anodes of 10micrometers diameter. The window size is 272 x 190 mm. The position is obtained by the charge division method. It is used to identify the source in the long rectangular field-of-view (1.5 x 80 degrees). Three cameras will be set to cover the 1.5 x 160 degrees arc. The position resolution is essentially important, which becomes better in the higher gas gain. We have tested gas mixtures of Xe+CO2with CO2 equals 0.2\%, 0.5\%, 1\%, 3%. The CO2 equals 0.5\% showed the most uniform gas gain, but has a little after pulses. We chose the Xe (99%) + CO2 (1%) combination for the flight counters. It can achieve the uniform gas gain in the cell and negligible after-pulse in high operating voltage. The engineering model of the counter (EM1) was build. We have tested the position resolution and the energy resolution across the counter. The position resolution and the energy resolution depend on the X-ray energy. On the basis of these results, together with the collimator response, we performed a realistic simulation.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The X-ray emission from the central region of the Galactic plane, |l, 54 pages, 12 figures, accepted for publication in ApJ Supplements Series

The Galactic ridge X-ray emission (GRXE) is an enhanced X-ray emission along the Galactic plane, whose origin still remains unknown. The GRXE was studied for the first time in the energy band of 0.5 –10 keV with a spatial resolution of 3′ by the ASCA Galactic plane survey which covers the spatial area of |l|≲45° and |b|≲0.4° almost uniformly. We determined the large scale distribution of the GRXE after eliminating discrete X-ray sources with a flux above10−12.5 ergs cm−2 s−1 and revealed that the volume emissivity of the GRXE is highly concentrated within the 4 kpc arm. We resolved 163 discrete X-ray sources by imaging analysis and obtained the LogN-LogS relations of those sources. In the hard (2–10 keV) band, the slope of the LogN−LogS relation is significantly smaller than 1. Considering a scale height of the Galactic plane covered by the ASCA Galactic plane survey, we conclude that the slope of the LogN−LogS relation represents that the spatial distribution of the sources has a scale height as small as...

The position dependency of gas amplification in the proportional counter (PC) is investigated. We have been developing one-dimensional position sensitive PCs for MAXI/GSC and HETE/WXM and found that anomalous gas amplification occurs in a high bias voltage, even while the PC is still operated in the proportional region. This effect depends on the position where the X-ray is absorbed. Therefore it appears as a hard tail, a soft tail, or a broad peak in the traditional PC, depending on the shape of the gain curve across the cell. It degrades the apparent energy resolution. Especially, a position sensitive proportional counter (PSPC) is operated with rather high bias voltage to give higher positional resolution. We encounter the difficulty to achieve good position and energy resolutions at the same time. In this work, we have examined the anomalous gas amplification for various gas mixtures of Xe + CO2, Ar + CO2 and Ar + CH4, for gas gain up to approximately 20000, and for energies from 6 to 17 keV to understand the phenomena.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Monitor of the All-sky X-ray Image (MAXI) is the first payload for the Japanese Experiment Module (JEM) on the International Space Station (ISS). It is designed for monitoring all-sky in the X-ray band. Its angular resolution and scanning period are about 1 arc-degree and 100 minutes, respectively. MAXI employs two types of X-ray camera. One is Gas Slit Camera (GSC), the detectors of which are one dimensional position sensitive proportional counters. Another is Solid-state Slit Camera (SSC). We mainly report on SSC. We employ a pair of SSCs, each of which consists of 16 CCD chips. Each CCD chips has 1024 X 1024 pixels, and the pixel size is 24 X 24 micrometer. The CCDs are to be operated at -60 degrees Celsius using Peltier coolers. Optical light is blocked by aluminum coat on the CCDs instead of fragile aluminized film. SSC achieves an energy resolution of 152 eV in FWHM at 5.9 keV. The energy range is 0.5 - 10 keV.

Monitor of All-sky X-ray Image (MAXI) is the first astrophysical payload which will be mounted on the Japanese Experiment Module Exposed Facility of International Space Station in 2004. It is designed for monitoring all-sky in the x-ray band by scanning with slat collimators and slit apertures. Its angular resolution and scanning period are approximately 1 arc degree and 90 minutes, respectively. MAXI employs two types of X-ray camera. One is Gas slit Camera (GSC), the detectors of which are 1D position sensitive proportional counters. Its position resolution is approximately 1.0 mm along carbon anode wires. GSC covers the 2.0 - 30 keV energy band. We have found an interesting feature in the energy response: monochromatic X-rays are detected with a peculiar hard tail in the spectra. The physical mechanism causing the hard tail is still unclear. The other camera is Solid-state Slit Camera (SSC). We employ a pair of SSCs, each of which consists of sixteen CCD chips. Each CCD has 1024 X 1024 pixels, and each pixel is 24 X 24 micrometers. The CCDs are to be operated at -60 degree using Peltier coolers. SSC covers an energy range of 0.5 - 10.0 keV. The test counters and test chips are evaluated in NASDA, Riken, and Osaka-University. The continuous Ethernet down link will enable us to alert the astronomers in all over the world to the appearance of X-ray transients, novae, bursts, flares etc. In this paper we will report on the current status of the MAXI mission.

MAXI is an X-ray all-sky monitor mission which will be deployed on the Japanese Experiment Module of the International Space Station in 2004. It is designed to monitor X-ray sources by scanning the entire sky every 90 minutes, and can detect X-ray sources of 3 mCrab in one day. Although its instantaneous field of view is limited to narrow fan beams, one can expect ∼5 GRBs to occur in the field of view and ∼25 afterglows to be detected per year.

A new pulsating X-ray source, AX J183220-0840, with a 1549.1-s period was discovered at R.A.= 18h32m20s and Dec.=-8d40'30'' (J2000, uncertainty=0.6degree) during an ASCA observation on the Galactic plane. The source was observed two times, in 1997 and in 1999. A phase-averaged X-ray flux of 1.1E-11 ergs cm-2 s-1 and pulsation period of 1549.1+/-0.4 s were consistently obtained from these two observations. The X-ray spectrum was represented by a flat absorbed power-law with a photon-index of =~0.8 and an absorption column density of =~1.3E22 cm-2. Also, a signature of iron K-shell line emission with a centroid of 6.7 keV and an equivalent width of approximately 450 eV was detected. From the pulsation period and the iron-line feature, AX J183220-0840 is likely to be a magnetic white dwarf binary with a complexly absorbed thermal spectrum with a temperature of about 10 keV., Comment: 13 pages, 4 figures, accepted for publication in ApJ Letters

Monitor of All-Sky X-ray Image (MAXI) is the first astrophysical payload for the Japanese Experiment Module (JEM) on the International Space Station. It is designed for monitoring all sky in the x-ray band. Two kinds of x-ray detectors, the gas slit camera and the solid-state slit camera, are employed. The former is the gas proportional counter with 1D position sensitivity and the latter is the x-ray CCD. We have designed and constructed the engineering models of both detectors. We have also developed an x-ray irradiation facility in the Tsukuba Space Center of National Space Development Agency of Japan. We report the status of the mission and introduce the x-ray irradiation facility.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

資料番号: SA1001054000

Since brainstem lesion involving dorsal (DR) and median raphe (MR) nuclei have been shown to induce gastric ulcers in fasted rats, the present study was carried out to determine the mechanisms mediating this effect of the lesion, inasmuch as there is indirect evidence for a close correlation between stress-induced gastric ulcers and central serotonergic activity. Acute and simultaneous lesion of both DR and MR in 48 h fasted rats induced a significantly high incidence of gastric ulcer at the end of a 48 h period of food deprivation. Acute selective lesion of either nucleus revealed that the MR nucleus is the structure whose inactivation is related to gastric ulceration. Ulcer incidence was also high in chronically lesioned rats fasted for the same period of time. Normally fed lesioned rats and sham-operated controls did not develop ulcers, indicating that ulcers only occurred when fasting and raphe lesion were combined. We conclude that the raphe nuclei may be involved in the etiology of stress-induced gastric ulcers. The possibility of disinhibition of a general stress-related central system by the raphe lesion is discussed as the main mechanism responsible for gastric ulceration.