Search

We present the results from the analysis of long Suzaku observations of the most X-ray luminous galaxy cluster RX J1347.5-1145 at z=0.451. Aims: We study physical properties of the hot (~20 keV) gas clump in the south-east (SE) region discovered by the Sunyaev-Zel'dovich (SZ) effect observations, to understand the gas physics of a violent cluster merger. We also explore a signature of non-thermal emission using the hard X-ray data. Results: We find that the single-temperature model fails to reproduce the continuum emission and Fe-K lines measured by XIS simultaneously. The two-temperature model with a very hot component improves the fit, although the XIS data can only give a lower bound on its temperature. We detect the hard X-ray emission in the 12-40 keV band at the 7 sigma level; however, the significance becomes marginal when the systematic error in the background estimation is included. With the Suzaku + Chandra joint analysis, we determine the temperature of the SE excess component to be 25.3^{+6.1}_{-4.5} ^{+6.9}_{-9.5} keV (90% statistical and systematic errors), which is in an excellent agreement with the previous SZ + X-ray analysis. This is the first time that the X-ray spectroscopy alone gives a good measurement of the temperature of the hot component in the SE region, which is made possible by Suzaku's unprecedented sensitivity to the wide X-ray band. These results strongly indicate that the cluster has undergone a recent, violent merger. The spectral analysis shows that the SE component is consistent with being thermal. We find the 3 sigma upper limit on the non-thermal flux, F < 8e-12 erg s^{-1} cm^{-2} in the 12-60 keV band. Combining this limit with a recent discovery of the radio mini halo at 1.4 GHz, we find a lower limit on the strength of the intracluster magnetic field, B > 0.007 micro G., 15 pages, 13 figures. Accepted for publication in A&A

Coagulation using aluminium salts is one of the most promising processes for the removal of colloidal matter and fine particles from raw water at purification plants. Recently, the composition of water entering water purification plants has become more complex and dosages of coagulants have been increasing. The sludges produced have become more difficult to dewater, and dewatering has become more expensive. To ensure economic operation of dewatering processes, it is essential to establish a relationship between sludge characteristics and dewaterability. Sludge dewatering is a complex process which is affected by various factors such as sludge total solids (TS), SiO2/Al2O3 ratio, ignition loss, and particle size distribution. This research developed a relationship between sludge dewaterability and particle size distribution. The particle size distribution could be easily measured using an automatic on-line device based on the laser diffraction method, with pre-conditioning using a propeller agitator which did not break up the flocs. The relationship developed is based on multiple linear regression analysis of the mean particle size (calculated from the particle size distribution), the floc ratio (a new parameter defined in this study), and Log(CST/TS) (CST = capillary suction time). The correlation between these factors explains the positive relationship found between the dewaterability and the particle size distribution of sludges, and shows that the relationship developed is widely applicable

著者人数: 16名, Accepted: 2006-09-20, 資料番号: SA1000366000