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A large-scale gradient in the metal abundance has been detected with ASCA from an X-ray bright cluster of galaxies AWM7. The metal abundance shows a peak of 0.5 solar at the center and smoothly declines to

High-quality X-ray spectra of NGC 4636 are obtained with ASCA. Theoretical models are found unable to reproduce the data in the Fe-L line region. Spectral data above 1.4 keV indicate that the Mg to Si abundance ratio is ~1 solar. Assuming that the abundance ratios among α elements are the same as the solar ratios, a spectral fit with increased systematic error in the 0.4-1.6 keV range gives abundances of α elements and Fe to be both ~1 solar by taking 1 solar of Fe to be 3.24×10−5 by number. These new abundance results solve the discrepancy between stellar and hot-gas metallicity, but still a low supernova rate is implied. We also detect strong abundance gradients for both α elements and iron in a similar fashion. The abundance is ~1 solar within 4' and decreases outward down to 0.2-0.3 solar at 10' from the galaxy center. Dilution due to an extended hot gas is suggested.

著者人数：16名, Accepted: 1996-12-26, 資料番号: SA1001064000

資料番号: SA1001088000

著者人数：16名, 資料番号: SA1001100000

We observed the BL Lac object Mrk 421 with the X-ray satellite ASCA in 1994 as part of a multifrequency observation. The 24 hr observation was conducted 1 day after the onset of a TeV flare detected by the Whipple Observatory and detected an X-ray flare, with no apparent variability in the optical, UV, and EGRET GeV flux. The ASCA 2-10 keV flux peaked at 3.7 ? 10-10 ergs cm-2 s-1 and then decreased to 1.8 ? 10-10 ergs cm-2 s-1 with a doubling timescale of ~12 hr. The shape of the X-ray spectrum varied during the observation, such that the hard X-rays always led the soft X-rays, both in brightening and dimming of the source, with a lag of the 0.5-1 keV photons versus those in the 2-7.5 keV band of ~1 hr. The rapid TeV variability indicates a compact TeV-producing region, suggesting relativistic beaming with a Doppler factor ? ? 5. The correlation of the flux in the X-ray and the TeV bands indicates that a high-energy tail of a single electron population is responsible for both X-rays and TeV ?-rays, with radio, IR, UV and X-rays produced via the synchrotron process and GeV and TeV ?-rays produced via Comptonization. Under the assumption that the soft lag observed in the X-ray band is due to the synchrotron-lifetime effects, with ? = 5, we calculate the magnetic field for the X-ray-producing region to be ~0.2 G. The Lorentz factors ?el of the electrons responsible for the emission in the keV and TeV bands are ~106, consistent with the values implied by the Klein-Nishina limit.

We observed two groups of galaxies, the NGC 5044 group (WP 23) and Hickson's compact group HCG 51, with ASCA. We detected an extended bright soft X-ray emission, which indicates the existence of large amounts of a hot X-ray emitting gas in both targets. The temperature of the hot gas is ~ 1 keV for both objects, which is equivalent to their galaxy velocity dispersion. The metal abundance of the gas is 0.3-0.5 solar value for both objects, which is similar to that of rich clusters of galaxies. The Si to Fe abundance ratio is smaller than that of rich clusters of galaxies, although the iron abundances determined by the Fe-L lines are somewhat uncertain. The X-ray luminosities in the 0.5-10 keV band are lxlO 43 erg s -1 and 5xl042erg s _1 for the NGC 5044 group and HCG 51, respectively, which are higher by an order of magnitude than those of X-ray bright elliptical galaxies. This makes HCG 51 one of the most X-ray luminous compact groups. Both objects have a total gravitating mass of Mtotai ~ 2.0 x 1013 M®, and a gas mass and a galaxy mass of Mgas ~ M gaiaxy ~1.5x 1012 M®. The ratios among these mass components are Mgas/Mgaiaxy ~ 1 and (Mgas+Mgaiaxy)/Mtotai ~ 0-2 within ~350 kpc for both objects. The latter is similar to previous ROSAT results for many groups of galaxies, while the former is larger than the average value of the ROSAT-observed groups. Moreover, the metal abundances of the present two groups are significantly higher than those of the NGC 2300 group and HCG 62, and are comparable to those of clusters. These suggest that the hot-gas mass and metal abundances can scatter widely among groups, compared to the small variance found among rich clusters.

著者人数：29名, 資料番号: SA1001099000

資料番号: SA1001101000

The SXS instrument is the Soft X-ray micro-calorimeter Spectrometer planned for the Japanese ASTRO-H satellite, scheduled to be launched in 2014. In this paper we describe the X-ray calibration sources used in this instrument. These sources use light sensitive photo-cathodes to generate electrons, which in turn generate the X-rays. This design has the unique property to allow for fast discrete pulsations of the generated X-rays. This enables the energy scale calibration of the instrument simultaneously with astronomical observations, without adding to the background in the astronomical data. Flight-model sources have been made, and a number of them have been operating in the past several months to monitor their behaviour. Here we report on the characterisation and performance of these sources. In addition, we will elaborate on the nature and expected accuracy of the energy calibration, in relation to the expected stability of the instrument, given the calibration source strength and its mode of operation.

DIOS (Diffuse Intergalactic Oxygen Surveyor) is a small scientific satellite with the main aim of searching warm-hot intergalactic medium using redshifted OVII and OVIII lines. The wide-field spectroscopic capability of DIOS will also bring rich science about the dynamics of cosmic hot plasmas in all spatial scales. The instrument will consist of a 4-stage X-ray telescope and an array of TES microcalorimeters with up to 400 pixels, cooled with mechanical coolers. Hardware development of DIOS and outstanding issues about the payload are described. DIOS will be further developed with international collaboration and will be proposed to the earliest call of JAXA’s small scientific satellite series.

LiteBIRD [Lite (Light) satellite for the studies of B-mode polarization and Inflation from cosmic background Radiation Detection] is a small satellite to map the polarization of the cosmic microwave background (CMB) radiation over the full sky at large angular scales with unprecedented precision. Cosmological inflation, which is the leading hypothesis to resolve the problems in the Big Bang theory, predicts that primordial gravitational waves were created during the inflationary era. Measurements of polarization of the CMB radiation are known as the best probe to detect the primordial gravitational waves. The LiteBIRD working group is authorized by the Japanese Steering Committee for Space Science (SCSS) and is supported by JAXA. It has more than 50 members from Japan, USA and Canada. The scientific objective of LiteBIRD is to test all the representative inflation models that satisfy single-field slow-roll conditions and lie in the large-field regime. To this end, the requirement on the precision of the tensor-to-scalar ratio, r, at LiteBIRD is equal to or less than 0.001. Our baseline design adopts an array of multi-chroic superconducting polarimeters that are read out with high multiplexing factors in the frequency domain for a compact focal plane. The required sensitivity of 1.8μKarcmin is achieved with 2000 TES bolometers at 100mK. The cryogenic system is based on the Stirling/JT technology developed for SPICA, and the continuous ADR system shares the design with future X-ray satellites.

Trabajo presentado a la conferencia: "Space Telescopes and Instrumentation: Ultraviolet to Gamma Ray" celebrada en Amsterdam (Holanda) el 1 de julio de 2012.-- et al., One of the instruments on the Advanced Telescope for High-Energy Astrophysics (Athena) which was one of the three missions under study as one of the L-class missions of ESA, is the X-ray Microcalorimeter Spectrometer (XMS). This instrument, which will provide high-spectral resolution images, is based on X-ray micro-calorimeters with Transition Edge Sensor (TES) and absorbers that consist of metal and semi-metal layers and a multiplexed SQUID readout. The array (32 x 32 pixels) provides an energy resolution of < 3 eV. Due to the large collection area of the Athena optics, the XMS instrument must be capable of processing high counting rates, while maintaining the spectral resolution and a low deadtime. In addition, an anti-coincidence detector is required to suppress the particle-induced background. Compared to the requirements for the same instrument on IXO, the performance requirements have been relaxed to fit into the much more restricted boundary conditions of Athena. In this paper we illustrate some of the science achievable with the instrument. We describe the results of design studies for the focal plane assembly and the cooling systems. Also, the system and its required spacecraft resources will be given. © (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

We found the intensity variations of OVII Kα line (0.56 keV) among the multiple observations of two blank sky fields toward NGC2992 and MBM16 with Suzaku. The OVII enhancement in the same line of sight are thought to be related to the Solar Wind Charge Exchange (SWCX) induced emission in the Helium Focusing Cone, depending the different observer's site by the yearly revolution around the Sun. We also simulated the SWCX induced OVII intensities reacted with the neutrals in the Heliosphere including the He Cone. The simulated OVII intensities were comparable to the observed intensity for MBM16 (dense molecular cloud within Local Hot Bubble), while the simulation amounted to about half of the observation for NGC2992. The origin of the half of observed OVII toward NGC2992 is thought to the distant hot plasma of our Galaxy.

Suzaku performed observations of 3 regions in and around the Shapley supercluster: a region located between A3558 and A3556, at ~0.9 times the virial radii of both clusters, and two other regions at 1° and 4° away from the first pointing. The 4°-offset observation was used to evaluate the Galactic foreground emission. We did not detect significant redshifted Oxygen emission lines (OVII and OVIII) in the spectra of all three pointings, after subtracting the contribution of foreground and background emission. An upper limit for the redshifted OVIII Kα line intensity of the warm-hot intergalactic medium (WHIM) is 1.5×10−7 photons s−1 cm−2 arcmin−2, which corresponds to an overdensity of ~380 (Z/0.1Z⊙)−1/2(L/3Mpc)−1/2, assuming T = 3×106 K. We found excess continuum emission in the 1°-offset and on-filament regions, represented by thermal models with kT ~1 keV and ~2 keV, respectively. The redshifts of both 0 and that of the supercluster (0.048) are consistent with the observed spectra. The ~1 keV emission ca...

X-ray properties of hot interstellar gas in a starburst galaxy NGC 253 were investigated to gain a further understanding of starburst-driven outflow activity by XMM-Newton and Suzaku. Spectroscopic analysis for three regions of the galaxy characterized by multiwavelength observations was conducted. The hot gas was represented by two thin thermal plasmas with temperatures of kT ~0.2 and ~0.6 keV. Abundance ratios i.e., O/Fe, Ne/Fe, Mg/Fe and Si/Fe, are consistent between three regions, which suggests the common origin of the hot gas. The abundance patterns are consistent with those of type II supernova ejecta, indicating that the starburst activity in the central region provides metals toward the halo through a galactic-scale starburst-driven outflow. The energetics also can support this indication on condition that 0.01-50 {\eta}^0.5 % of the total emission in the nuclear region has flowed to the halo region. To constrain the dynamics of hot interstellar gas, surface brightness and hardness ratio profiles which trace the density and temperature were extracted. Assuming a simple polytropic equation of state of gas, T{\rho}^(1-{\gamma}) = const, we constrained the physical condition. {\gamma} is consistent with 5/3 at the hot disk and T is constant ({\gamma} = 1) in the halo. It is suggested that the hot gas expands adiabatically from the central region towards the halo region while it moves as free expansion from the inner part of the halo towards the outer part of the halo as the outflow. We constrained the outflow velocity to be >100 km s^-1 from the observed temperature gradient in the halo. In comparison with the escape velocity of ~220 km s^-1 for NGC 253, it is indicated that the hot interstellar gas can escape from the gravitational potential of NGC 253 by combining the outflow velocity and the thermal velocity., Comment: 10 figures, accepted by PASJ

A bright, nearby edge-on starburst galaxy NGC 253 was studied using the Suzaku, XMM and Chandra X-ray observatories. Here, we focused on Suzaku and Chandra studies because of a good energy resolution with a low background and a sub-arcsecond spatial resolution. We detected with Suzaku complex line structure of Fe K, which is resolved into three lines (FeI at 6.4 keV, FeXXV at 6.7 keV and FeXXVI at 7.0 keV) around the center of NGC 253. Especially, the FeI and FeXXVI lines are the first clear detections, with a significance of >99.99% and 99.89% estimated by a Monte Carlo procedure. Imaging spectroscopy with Chandra revealed that the emission is distributed in ~60 arcsec2 region around the nucleus, which suggests that the source is not only the buried AGN.

We present a detailed structural study of the hot ISM in the Galactic halo along the sight line toward the bright active galactic nucleus Mkn 421. The O VII and O VIII absorption lines were measured with the Low Energy Transmission Grating Spectrograph aboard Chandra toward Mkn 421, and the O VII and O VIII emission lines were observed in the vicinities of the sight line with the X-ray Imaging Spectrometer aboard Suzaku. We jointly analyzed the absorption and the emission spectra assuming exponential distributions of the gas temperature and density from the Galactic plane, and constrained the temperature and density at the plane to be 2.7(+0.6,-0.5)×106 K and 1.5(+0.7,-0.5)×10−3 cm−3, with the scale heights of 1.6(+3.6,-0.9)kpc and 5.1(> 1.2)kpc respectively. The results are consistent with those obtained in the LMC X-3 direction and the PKS 2155-304 direction, describing a thick disk-like hot gas with its height of a few kpc from the Galactic plane.

Microelectromechanical systems (MEMS) micropore X-ray optics were proposed as an ultralightweight, high- resolution, and low cost X-ray focusing optic alternative to the large, heavy and expensive optic systems in use today. The optic's monolithic design which includes high-aspect-ratio curvilinear micropores with minimal sidewall roughness is challenging to fabricate. When made by either deep reactive ion etching or X-ray LIGA, the micropore sidewalls (re ecting surfaces) exhibit unacceptably high surface roughness. A magnetic eld-assisted nishing (MAF) process was proposed to reduce the micropore sidewall roughness of MEMS micropore optics and improvements in roughness have been reported. At this point, the best surface roughness achieved is 3 nm Rq on nickel optics and 0.2 nm Rq on silicon optics. These improvements bring MEMS micropore optics closer to their realization as functional X-ray optics. This paper details the manufacturing and post-processing of MEMS micropore X-ray optics including results of recent polishing experiments with MAF.

We report a novel micromachined X-ray optics using DRIE formed micro mirrors for future space astronomical missions. We have fabricated a test optics and measured its imaging quality using X-rays. We have successfully verified the X-ray focusing using this type of optics for the first time in the world. The obtained angular resolution was about 20 arcmin and 3.1 mm. This result was consistent with the expected angular resolution based on the surface roughness of the DRIE formed side walls. To achieve a better angular resolution, we will condition annealing and magnetic field assisted finishing processes.

A bright, nearby edge-on starburst galaxy NGC 253 was studied using the Suzaku, XMM and Chandra X-ray observatories. We detected with Suzaku and XMM complex line structure of Fe K, which is resolved into three lines (Fe I at 6.4 keV, Fe XXV at 6.7 keV and Fe XXVI at 7.0 keV) around the center of NGC 253. Especially, the Fe I and Fe XXVI lines are the first clear detections, with a significance of >99.99 % and 99.89 % estimated by a Monte Carlo procedure. Imaging spectroscopy with Chandra revealed that the emission is distributed in ~60 arcsec^2 region around the nucleus, which suggests that the source is not only the buried AGN. The flux of highly ionized Fe lines can be explained by the accumulation of 10-1000 supernova remnants that are the result of high starforming activity, while the Fe I line flux is consistent with the fluorescent line emission expected with the molecular clouds in the region., Accepted for publication in ApJL

著者人数：12名, 資料番号: SA1001083000

X-ray optics based on MEMS technologies can provide future astronomical missions with ultra light-weight and high-performance optical systems. Curvilinear micropores vertical to a thin wafer are made by using DRIE (Deep Reactive Ion Etching) or X-ray LIGA. The side walls are smoothed by using magnetic field assisted finishing and annealing technologies in order that the walls can reflect X-rays. Two or four such wafers are bent to spherical shapes with different curvature of radii and stacked, to focus parallel X-rays from astronomical objects by multiple reflections. In this paper, the concept and recent advances of the MEMS X-ray optics are reviewed.

We are developing an ASTRO-H data analysis framework with the Geant4-based Monte Carlo simulation core, and numerical models of the on-orbit environmental radiation and full-satellite mass structure. In addition, the framework also includes a mechanism to connect and control data processing modules that are developed independently and data communication channels among them, which has been technically proven by simulations and analysis of the Suzaku HXD, many other detectors and astrophysical issues.

The Soft X-ray Spectrometer (SXS) instrument on the Astro-H observatory is based on a 36 pixel x-ray calorimeter array cooled to 50 mK in a sophisticated spaceflight cryostat. The SXS is a true spatial-spectral instrument, where each spatially discrete pixel functions as a high-resolution spectrometer. Here we discuss the SXS detector subsystem that includes the detector array, the anticoincidence detector, the first stage amplifiers, the thermal and mechanical staging of the detector, and the cryogenic bias electronics. The design of the SXS detector subsystem has significant heritage from the Suzaku/XRS instrument but has some important modifications that increase performance margins and simplify the focal plane assembly. Notable improvements include x-ray absorbers with significantly lower heat capacity, improved load resistors, improved thermometry, and a decreased sensitivity to thermal radiation. These modifications have yielded an energy resolution of 3.5-4.0 eV FWHM at 6 keV for representative devices in the laboratory, giving considerable margin against the 7 eV instrument requirement. We expect similar performance in flight.

The SXS instrument is the Soft X-ray micro-calorimeter Spectrometer planned for the Japanese ASTRO-H satellite, scheduled to be launched in 2014. In this paper, the trade off and modelling for the X-ray absorption and optical blocking filters will be described. The X-ray absorption filter will optimize the efficiency for high spectral resolution observations for bright sources at higher energies (notably around the Fe-K line at 6.4 KeV), given the characteristics of the instrument while the optical blocking filter allows X-ray observations of optically bright sources. For this mission a novel type of on-off-switchable X-ray calibration source, using light sensitive photo-cathodes, is being developed, which will be used for gain calibration and contamination monitoring. These sources will be used by both the SXS and SXI (Soft X-ray Imager) instruments and have the capability to be pulsed at millisecond intervals. Details of these sources will also be discussed.

We present the science and an overview of the Soft X-ray Spectrometer onboard the ASTRO-H mission with emphasis on the detector system. The SXS consists of X-ray focusing mirrors and a microcalorimeter array and is developed by international collaboration lead by JAXA and NASA with European participation. The detector is a 6×6 format microcalorimeter array operated at a cryogenic temperature of 50 mK and covers a 3' ×3' field of view of the X-ray telescope of 5.6 m focal length. We expect an energy resolution better than 7 eV (FWHM, requirement) with a goal of 4 eV. The effective area of the instrument will be 225 cm 2 at 7 keV; by a factor of about two larger than that of the X-ray microcalorimeter on board Suzaku. One of the main scientific objectives of the SXS is to investigate turbulent and/or macroscopic motions of hot gas in clusters of galaxies.

The Soft X-ray Spectrometer (SXS) is a cryogenic high resolution X-ray spectrometer onboard the X-ray astronomy satellite ASTRO-H. The detector array is cooled down to 50 mK using a 3-stage adiabatic demagnetization refrigerator (ADR). The cooling chain from room temperature to the ADR heat-sink is composed of superfluid liquid He, a 4He Joule-Thomson cryocooler, and 2-stage Stirling cryocoolers. It is designed to keep 30 L of liquid He for more than 3 years in the nominal case. It is also designed with redundant subsystems throughout from room temperature to the ADR heat-sink, to alleviate failure of a single cryocooler or loss of liquid He.

DIOS (Diffuse Intergalactic Oxygen Surveyor) is a small scientific satellite with a main aim for the search of warm-hot intergalactic medium using redshifted OVII and OVIII lines. The instrument will consist of a 4-stage X-ray telescope and an array of TES microcalorimeters with 256 pixels, cooled with mechanical coolers. Hardware development of DIOS and the expected results are described. Survey observations over about 5° x 5° area will reveal new filamentary structures. DIOS will be proposed to the 3rd mission in JAXA's small satellite series in 2011, aiming for launch around 2016 if it will be selected.

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe by performing high-resolution, high-throughput spectroscopy with moderate angular resolution. ASTRO-H covers very wide energy range from 0.3 keV to 600 keV. ASTRO-H allows a combination of wide band X-ray spectroscopy (5-80 keV) provided by multilayer coating, focusing hard X-ray mirrors and hard X-ray imaging detectors, and high energy-resolution soft X-ray spectroscopy (0.3-12 keV) provided by thin-foil X-ray optics and a micro-calorimeter array. The mission will also carry an X-ray CCD camera as a focal plane detector for a soft X-ray telescope (0.4-12 keV) and a non-focusing soft gamma-ray detector (40-600 keV) . The micro-calorimeter system is developed by an international collaboration led by ISAS/JAXA and NASA. The simultaneous broad bandpass, coupled with high spectral resolution of Delta E ~7 eV provided by the micro-calorimeter will enable a wide variety of important science themes to be pursued., 18 pages, 12 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2010: Ultraviolet to Gamma Ray"

One of the instruments on the International X-ray Observatory (IXO), under study with NASA, ESA and JAXA, is the X-ray Microcalorimeter Spectrometer (XMS). This instrument, which will provide high spectral resolution images, is based on X-ray micro-calorimeters with Transition Edge Sensor thermometers. The pixels have metallic X-ray absorbers and are read-out by multiplexed SQUID electronics. The requirements for this instrument are demanding. In the central array (40 x 40 pixels) an energy resolution of < 2.5 eV is required, whereas the energy resolution of the outer array is more relaxed (≈ 10 eV) but the detection elements have to be a factor 16 larger in order to keep the number of read-out channels acceptable for a cryogenic instrument. Due to the large collection area of the IXO optics, the XMS instrument must be capable of processing high counting rates, while maintaining the spectral resolution and a low deadtime. In addition, an anti-coincidence detector is required to suppress the particle-induced background. In this paper we will summarize the instrument status and performance. We will describe the results of design studies for the focal plane assembly and the cooling systems. Also the system and its required spacecraft resources will be given.

A microcalorimeter array based on a transition-edge sensor (TES) thermometer is a promising imaging spectrometer for use in future x-ray astronomy missions. A TES microcalorimeter achieves eV energy resolution and an array of >100 pixels also provides a moderate imaging capability. For a large format array, signal multiplexing at the low temperature stage is mandatory in order to reduce heat loads from cold stage preamplifiers and through wirings. We are developing frequency division multiplexing (FDM). In FDM, each TES is ac-biased with a different carrier frequency. Signals from several pixels are summed and then read out by one dc SQUID (superconducting quantum interference device). The maximum number of multiplexed pixels is limited by the bandwidth of a SQUID in a flux-locked loop. Assuming 1 m cable length between the room temperature and the cold stage, the bandwidth is only

We have been developing ultra light-weight X-ray optics using MEMS (Micro Electro Mechanical Systems) technologies.We utilized crystal planes after anisotropic wet etching of silicon (110) wafers as X-ray mirrors and succeeded in X-ray reflection and imaging. Since we can etch tiny pores in thin wafers, this type of optics can be the lightest X-ray telescope. However, because the crystal planes are alinged in certain directions, we must approximate ideal optical surfaces with flat planes, which limits angular resolution of the optics on the order of arcmin. In order to overcome this issue, we propose novel X-ray optics based on a combination of five recently developed MEMS technologies, namely silicon dry etching, X-ray LIGA, silicon hydrogen anneal, magnetic fluid assisted polishing and hot plastic deformation of silicon. In this paper, we describe this new method and report on our development of X-ray mirrors fabricated by these technologies and X-ray reflection experiments of two types of MEMS X-ray mirrors made of silicon and nickel. For the first time, X-ray reflections on these mirrors were detected in the angular response measurements. Compared to model calculations, surface roughness of the silicon and nickel mirrors were estimated to be 5 nm and 3 nm, respectively.

A high‐energy‐resolution energy dispersive spectrometer (EDS) utilizing a TES (transition edge sensor) microcalorimeter array is developed for a transmission electron microscope (TEM). The goals of the development are (1) an energy range of 0.3–10 keV, (2) an energy resolution of FWHM

Arrays of transition edge sensor (TES) X‐ray microcalorimeters can provide a high energy resolution and a large area necessary for future dark baryon search missions such as DIOS (Diffuse Intergalactic Oxygen Surveyor). In the current design, the energy resolution of 2 eV at 0.3–1.5 keV and the geometrical area of 1 cm2 are required for DIOS. As an R&D study, we fabricated a 16×16 Ti/Au bilayer TES array without an absorber, and achieved the energy resolution of 4.4±0.2 eV at 5.9 keV. Considering the recent experimental results on so‐called excess noise, we investigated a detailed design of the TES array for DIOS. We concluded that we need a at least 20×20 pixel array consisting of 250 μm‐square TESs and 500 μm‐square mushroom‐type Bi/Au absorbers. We discussed technical issues to manufacture such a large format array.

We invented novel ultra-lightweight and high-resolution MEMS (Micro Electro Mechanical Systems) X-ray optics for space X-ray telescopes. As a first step of R&D, we conducted optical image analysis of a spherically-shaped test optic with a radius of curvature of 1000 mm. Focusing of the parallel light was verified with our optic for the first time.

Our recent development of transition-edge sensor (TES) microcalorimeters for future X-ray astronomical missions such as DIOS is reported. In-house micromaching processes has been established aiming at prompt fabrication of TES devices. With a single-pixel TES microcalorimeter and an Au absorber, the energy resolution of 4.8 eV at 5.9 keV is achieved. 16×16 pixel arrays of TES microcalorimeters are successfully fabricated by using deep dry etching technique. The energy resolution is 11 eV and 26 eV with and without an Au absorber, respectively. The worse energy resolution than a single-pixel TES is due to large decrease of TES sensitivity and increase of transition temperature after etching. The reason for these phenomena is under investigation. In parallel, mushroom-type Au absorber structures are being tested. Furthermore, to precisely measure TES sensitivities and heat capacity, an experimental setup for impedance measurements is established.

X-ray reflectivity of an ultra light-weight X-ray optic using MEMS technologies was measured in two different energies (0.28 keV and 1.49 keV). The obtained reflectivities can be understood by considering the mirror surface structures.

The Soft X-ray Spectrometer (SXS) onboard the NeXT (New exploration X-ray Telescope) is an X-ray spectrometer utilizing an X-ray microcalorimeter array. Combined with the soft X-ray telescope of 6 m focal length, the instrument will have a ~ 290cm 2 effective at 6.7 keV. With the large effective area and the energy resolution as good as 6 eV (FWHM), the instrument is very suited for the high-resolution spectroscopy of iron K emission line. One of the major scientific objectives of SXS is to determine turbulent and/or macroscopic motions of the hot gas in clusters of galaxies of up to z ~ 1. The instruments will use 6 × 6 or 8 × 8 format microcalorimeter array which is similar to that of Suzaku XRS. The detector will be cooled to a cryogenic temperature of 50 mK by multi-stage cooling system consisting of adiabatic demagnetization refrigerator, super fluid He, a 3He Joule Thomson cooler, and double-stage stirling cycle cooler.

The SXS (Soft X-ray Spectrometer) onboard the coming Japanese X-ray satellite NeXT (New Exploration Xray Telescope) and the SXC (Spectrum-RG X-ray Calorimeter) in Spectrum-RG mission are microcalorimeter array spectrometers which will achieve high spectral resolution of ~ 6 eV in 0.3-10.0 keV energy band. These spectrometers are well-suited to address key problems in high-energy astrophysics. To achieve these high spectral sensitivities, these detectors require to be operated under 50 mK by using very efficient cooling systems including adiabatic demagnetization refrigerator (ADR). For both missions, we propose a two-stage series ADR as a cooling system below 1 K, in which two units of ADR consists of magnetic cooling material, a superconducting magnet, and a heat switch are operated step by step. Three designs of the ADR are proposed for SXS/SXC. In all three designs, ADR can attain the required hold time of 23 hours at 50 mK and cooling power of 0.4μW with a low magnetic fields (1.5/1.5 Tesla or 2.0/3.0 Tesla) in a small configuration (180 mmφ× 319 mm in length). We also fabricated a new portable refrigerator for a technology investigation of two-stage ADR. Two units of ADR have been installed at the bottom of liquid He tank. By using this dewar, important technologies such as an operation of two-stage cooling cycle, tight temperature control less than 1 μK (in rms) stability, a magnetic shielding, saltpills, and gas-gap heat switches are evaluated.

The NeXT (New exploration X-ray Telescope), the new Japanese X-ray Astronomy Satellite following Suzaku, is an international X-ray mission which is currently planed for launch in 2013. NeXT is a combination of wide band X-ray spectroscopy (3 - 80 keV) provided by multi-layer coating, focusing hard X-ray mirrors and hard X-ray imaging detectors, and high energy-resolution soft X-ray spectroscopy (0.3 - 10 keV) provided by thin-foil X-ray optics and a micro-calorimeter array. The mission will also carry an X-ray CCD camera as a focal plane detector for a soft X-ray telescope and a non-focusing soft gamma-ray detector. With these instruments, NeXT covers very wide energy range from 0.3 keV to 600 keV. The micro-calorimeter system will be developed by international collaboration lead by ISAS/JAXA and NASA. The simultaneous broad bandpass, coupled with high spectral resolution of Delta E ~ 7 eV by the micro-calorimeter will enable a wide variety of important science themes to be pursued., 14 pages, 10 figures, Proceedings of the SPIE meeting, "Space Telescopes and Instrumentation II: Ultraviolet to Gamma Ray 2008", Marseille (2008)

We present the current status of a small X-ray mission DIOS (Diffuse Intergalactic Oxygen Surveyor), consisting of a 4-stage X-ray telescope and an array of TES microcalorimeters, cooled with mechanical coolers, with a total weight of about 400 kg. The mission will perform survey observations of warm-hot intergalactic medium using OVII and OVIII emission lines, with the energy coverage up to 1.5 keV. The wide field of view of about 50' diameter, superior energy resolution close to 2 eV FWHM, and very low background will together enable us a wide range of science for diffuse X-ray sources. We briefly describe the current status of the development of the satellite, and the subsystems.

Spatially resolved X-ray spectroscopy with high spectral resolution allows the study of astrophysical processes in extended sources with unprecedented sensitivity. This includes the measurement of abundances, temperatures, densities, ionisation stages as well as turbulence and velocity structures in these sources. An X-ray calorimeter is planned for the Russian mission Spektr Rontgen-Gamma (SRG), to be launched in 2011. During the first half year (pointed phase) it will study the dynamics and composition of of the hot gas in massive clusters of galaxies and in supernova remnants (SNR). During the survey phase it will produce the first all sky maps of line-rich spectra of the interstellar medium (ISM). Spectral analysis will be feasible for typically every 5° x 5° region on the sky. Considering the very short time-scale for the development of this instrument it consists of a combination of well developed systems. For the optics an extra eROSITA mirror, also part of the Spektr-RG payload, will be used. The detector will be based on spare parts of the detector flown on Suzaku combined with a rebuild of the electronics and the cooler will be based on the design for the Japanese mission NeXT. In this paper we will present the science and give an overview of the instrument.

Multiplexed readout of TES (Transition Edge Sensor) signals is one of the key technologies needed to realize large format arrays of microcalorimeters in future X-ray missions. In the FDM (Frequency-Domain Multiplexing) approach using MHz biasing frequencies, a wide band-width FLL (Flux Locked Loop) circuit is essential to compensate the phase delay between the TES sensor and the room temperature circuits. An analog feedback circuit using a lock-in amplifier technique and phase shifters with a very low noise pre-amplifier is being developed. This circuit will be tested with an actual TES array and an 8-input SQUID in the EURECA project.

We carried out observations of the central and 20’ east offset regions of the cluster of galaxies Abell 1060 with Suzaku. Spatially resolved X-ray spectral=analysis has revealed temperature and abundance profiles of Abell 1060 out to 27’0≃380 h−1 70 kpc, which corresponded to ∼0.3 γvir. The temperature decrease of the intra cluster medium from 3.4 keV at the center to 2.2 keV in the outskirt region are clearly observed. Si, S and Fe abundances also decrease by more than 50% from the center to the outer parts, while Mg shows a fairly constant abundance of ∼ 0.7 solar within γ 13’).Results on temperature and abundances of Si, S, and Fe are consistent with those derived by XMM-Newton atγ < 13’ The formation and metal enrichment of the cluster are discussed based on implications of our results.

We studied the properties of the intra‐cluster medium (ICM) in two clusters of galaxies (AWM 7 and Abell 1060) and two groups (HCG 62 and NGC 507) observed with the 5th Japanese X‐ray astronomical satellite, Suzaku. We measured for the first time precise cumulative ICM metal masses and distributions for various elements, such as O, Ne, Mg, Si, S, Fe, within 0.1 and ∼0.3 r180. Because of the good XIS sensitivity to emission lines, especially below 2 keV, we directly measured O and Mg line intensities and obtained abundances. Comparing our results with supernova nucleosynthesis models, the number ratio of Type II (SNe II) to Type Ia (SNe Ia) is estimated to be ∼3.5, assuming the metal mass in the ICM is represented by the sum of products synthesized in SNe Ia and SNe II. Normalized by the K‐band luminosities of present galaxies, and including the metals in stars, the integrated number of past SNe II explosions is estimated to be close to or somewhat higher than the star formation rate determined from Hubble...

About half of the baryons in the local Universe are thought to reside in the so-called warm-hot intergalactic medium (WHIM) at temperatures of 0.1-10 million K. Thermal soft excess emission in the spectrum of some cluster outskirts that contains OVII and/or OVIII emission lines is regarded as evidence of the WHIM, although the origin of the lines is controversial due to strong Galactic and solar system foreground emission. We observed the Coma-11 field, where the most prominent thermal soft excess has ever been reported, with Suzaku XIS in order to make clear the origin of the excess. We did not confirm OVII or OVIII excess emission. The OVII and OVIII intensity in Coma-11 is more than 5 sigma below that reported before and we obtained 2 sigma upper limits of 2.8 and 2.9 photons cm^-2 s^-1 sr^-1 for OVII and OVIII, respectively. The intensities are consistent with those in another field (Coma-7) that we measured, and with other measurements in the Coma outskirts (Coma-7 and X Com fields with XMM-Newton). We did not confirm the spatial variation within Coma outskirts. The strong oxygen emission lines previously reported are likely due to solar wind charge exchange., Comment: 5 pages, 3 figures. Accepted for publication in ApJ

著者人数: 17名, Accepted: 2007-10-27, 資料番号: SA1000644000