Study of the Intracluster and Intergalactic Medium in the Sculptor Supercluster with Suzaku

We studied the high temperature plasma in the direction of the Sculptor supercluster at z=0.108 with Suzaku. Suzaku carried out four observations in the supercluster: namely, A2811, A2811 offset, A2804, A2801 regions in 2005 Nov.--Dec., including the regions beyond the virial radii of these clusters. The study needed precise background estimation because the measured intensity of the redshifted lines, especially those from oxygen, were strongly affected by the the Galactic emission. The spectra taken in the regions outside of the virial radii of the member clusters were used as the background which included both the Galactic and Cosmic X-ray Background (CXB) components. We also used the background data which were taken near the Sculptor supercluster. Temperature and metal abundance profiles were determined to the virial radii of the member clusters, and then we searched for the oxygen line emission in the region outside of the virial radii of the clusters. As a result, the temperature of the clusters decreased toward the virial radii, and the spectral fits for the filament region did not require extra component other than the Galactic and CXB components. We constrained the intensities of O VII and O VIII lines to be less than 8.1 and 5.1 photons cm^-2 s^-1 arcmin^-2, respectively, as 2-sigma upper limits. The intensity of O VII indicates n_H < 1.6e-5 cm^-3 (Z/0.1 Z_solar)^-1/2 (L/25 Mpc)^-1/2, which corresponds to an over density, delta < 60 (Z/0.1 Z_solar)^-1/2 (L/25 Mpc)^-1/2.Comment: 11 pages, 8 figures, accepted for publication in PAS

Suzaku and XMM-Newton Observations of the Fornax cluster: Temperature and Metallicity Distribution

Suzaku observed a central region and five offset regions within 0.2 r180 in the Fornax cluster, a nearby poor cluster, and XMM-Newton mapped the cluster with 15 pointings out to 0.3 r180. The distributions of O, Mg, Si, S, and Fe in the intracluster medium (ICM) were studied with Suzaku, and those of Fe and temperature were studied with XMM. The temperature of the ICM gradually decreases with radius from 1.3 keV at 0.04 r180 to 1 keV at 0.2-0.3 r180. If the new solar abundances of Lodders et al. (2003) and a single-temperature plasma model are adopted, O, Mg, Si, S, and Fe show similar abundances: 0.4-0.6 solar within 0.02-0.2 r180. This Fe abundance is similar to those at 0.1-0.2 r180 in rich clusters and other groups of galaxies. At 0.2-0.3 r180, the Fe abundance becomes 0.2-0.3 solar. A two-temperature plasma model yields ICM abundances that are higher by a factor of 1.2-1.5, but gives similar abundance ratios among O, Mg, Si, S, and Fe. The northern region has a lower ICM temperature and higher brightness and Fe abundance, whereas the southern region has a higher ICM temperature and lower brightness and Fe abundance. These results indicate that the cD galaxy may have traveled from the north because of recent dynamical evolution. The cumulative oxygen- and iron-mass-to-light ratios within 0.3 r180 are more than an order of magnitude lower than those of rich clusters and some relaxed groups of galaxies. Past dynamical evolution might have hindered the strong concentration of hot gas in the Fornax cluster's central region. Scatter in the IMLR and similarity in the element abundances in the ICM of groups and clusters of galaxies indicate early metal synthesis.Comment: 15 pages, 13 figures, accepted for publication in PAS

Search for X-Ray Emission Associated with the Shapley Supercluster with Suzaku

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{\deg}and 4{\deg}away from the first pointing. The 4{\deg}-offset observation was used to evaluate the Galactic foreground emission. We did not detect significant redshifted Oxygen emission lines (O VII and O VIII) in the spectra of all three pointings, after subtracting the contribution of foreground and background emission. An upper limit for the redshifted O VIII Ka line intensity of the warm-hot intergalactic medium (WHIM) is 1.5 \times 10^-7 photons s^-1 cm^-2 arcmin^-2, which corresponds to an overdensity of ~380 (Z/0.1 Z_solar)^{-1/2} (L/3 Mpc)^{-1/2}, assuming T=3\times10^6 K. We found excess continuum emission in the 1{\deg}-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 can be also fitted with Ne-rich Galactic (zero redshift) thin thermal emission. Radial intensity profile of 2 keV component suggests contribution from A3558 and A3556, but with significant steepening of the intensity slope in the outer region of A3558. Finally, we summarized the previous Suzaku search for the WHIM and discussed the feasibility of constraining the WHIM. An overdensity of < 400 can be detectable using O VII and O VIII emission lines in a range of 1.4\times10^6 K < T < 5\times10^6 K or a continuum emission in a relatively high temperature range T > 5\times10^6 K with the Suzaku XIS. The non detection with Suzaku suggests that typical line-of-sight average overdensity is < 400

<所内学術研究成果報告>L. 水の科学と高周波分光

糖はその分子内に多数のOH基を有する有機物であり,水溶液中で変旋光を示す。D-glucoseでは,水溶液中で1位のOH基の立体配置に基づくα, β異性化が起こるため,糖分子周囲の水和構造にも変化が生じると考えられる。高周波分光法は,溶液構造変化あるいは分子同士の会合状態変化を鋭敏に検出することが可能である。今回,D-glucoseのα, β異性化反応過程を高周波分光法により追跡し,1800MHz付近の共振ピークが反応時間によってその吸収強度に変化が生じることを見出した。吸収強度変化は,異性化反応時間との間に直線関係が成立し,比旋光度変化との間にも良い相関が得られた

Suzaku Observations of the cluster of galaxies Abell 2052

The results from Suzaku XIS observations of the relaxed cluster of galaxies Abell2052 are presented. Offset pointing data are used to estimate the Galactic foreground emission in the direction to the cluster. Significant soft X-ray excess emission above this foreground, the intra-cluster medium emission, and other background components is confirmed and resolved spectroscopically and radially. This excess can be described either by (a) local variations of known Galactic emission components or (b) an additional thermal component with temperature of about 0.2 keV, possibly associated with the cluster. The radial temperature and metal abundance profiles of the intra-cluster medium are measured within \sim 20 in radius (about 60% of the virial radius) from the cluster center . The temperature drops radially to 0.5-0.6 of the peak value at a radius of \sim 15'. The gas-mass-weighted metal abundance averaged over the observed region is found to be 0.21 +- 0.05 times solar.Comment: Accepted for publication in PASJ (2008), 19 pages, postscript figure

Efficacy of 23-valent pneumococcal vaccine in preventing pneumonia and improving survival in nursing home residents: double blind, randomised and placebo controlled trial

Objective To determine the efficacy of a 23-valent pneumococcal polysaccharide vaccine in people at high risk of pneumococcal pneumonia

On the lack of strong O-line excess in the Coma cluster outskirts from Suzaku

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 Ap

Measurement of the Fluctuation of Structures by Reflection of Laser Beam. I

Measurement and analysis of fluctuations of structural objects are useful for monitoring the condition of these structures. In this paper, we propose a laser beam technique for studying these fluctuations, and report some results of our investigations, including an observation of forced vibration of a refrigerator, rotational frequency of an electric motor, and the appearance of a fluctuation in rotational speed due to fatigue. This technique has also been applied to real structural objects, a resonance of a automobile due to rotation of the engine, and intrinsic vibrations of buildings. Standard techniques used in fluctuation analysis are compared in a detection of an abnormal state of an electric motor. Data processing techniques of higher-orders are tested. Fluctuation analysis should be an important objective of analytical chemistry. The results obtained with this laser beam technique should form a useful collection of data regarding fluctuation analysis of various objects