著者

Mizuno Tsunefumi Miyawaki Ryohei Ebisawa Ken KUBOTA Aya MIYAMOTO Masao WINTER Lisa UEDA Yoshihiro ISOBE Naoki MAKISHIMA Kazuo

出版者

Published for the Yukawa Institute for Theoretical Physics and the Physical Society of Japan

雑誌

Progress of theoretical physics. Supplement (ISSN:03759687)

巻号頁・発行日

no.169, pp.229-233, 2007-12-19

参考文献数

24

被引用文献数

1

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We report about the Suzaku observation of two ultraluminous X-ray sources (ULXs), X-1 and X-2, in NGC1313, together with their spectra by XMM-Newton. During the observation, both showed intensity-correlated spectral changes. The brighter source, X-1, exhibited the highest luminosity (~3×10^<40>erg s^<-1>) ever recorded from this source. Its spectral variation is ascribed to a strong power-law like component with a mild high energy curvature, while about 10% of the flux is carried by a stable soft component modeled by a cool disk emission. These properties suggest that the source was in the "very high" state, wherein the disk emission is strongly Comptonized and the optically-thick disk is truncated at a large radii or cooled off. The spectrum of X-2 is best represented, in its fainter phase, by a multicolor disk model with the innermost disk temperature of 1.2-1.3keV, and becomes flatter as the source gets brighter. Hence X-2 is interpreted to be in a slim disk state. These results suggest that the two ULXs host black holes of a few tens to a few hundreds solar masses.

著者

Mizuno Tsunefumi Miyawaki Ryohei Ebisawa Ken KUBOTA Aya MIYAMOTO Masao WINTER Lisa M. UEDA Yoshihiro ISOBE Naoki DEWANGAN Gulab C. DONE Chris GRIFFITHS Richard E. HABA Yoshito KOKUBUN Motohide KOTOKU Jun'ichi MAKISHIMA Kazuo MATSUSHITA Kyoko MUSHOTZKY Richard F. NAMIKI Masaaki PETRE Robert TAKAHASHI Hiromitsu TAMAGAWA Toru TERASHIMA Yuichi

出版者

日本天文学会

雑誌

PASJ : publications of the Astronomical Society of Japan (ISSN:00046264)

巻号頁・発行日

vol.59, no.1, pp.S257-S267, 2007-01-31

参考文献数

56

被引用文献数

2

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Two ultraluminous X-ray sources (ULXs) in the nearby Sb galaxy NGC 1313, named X-1 and X-2, were observed with Suzaku on 2005 September 15. During the observation for a net exposure of 28 ks (but over a gross time span of 90 ks), both objects varied in intensity by about 50%. The 0.4–10 keV X-ray luminosities of X-1 and X-2 were measured as 2.5×1040 ergs-1 and 5.8×1039 ergs-1, respectively, with the former exhibiting the highest ever reported for this ULX. The spectrum of X-1 can be explained by the sum of a strong and variable powerlaw component with a high-energy cutoff, and a stable multicolor blackbody with an innermost disk temperature of ∼ 0.2keV. These results suggest that X-1 was in a "very high" state, where disk emission is strongly Comptonized. The absorber within NGC 1313 toward X-1 is suggested to have a subsolar oxygen abundance. The spectrum of X-2 is best represented, in its fainter phase, by a multicolor blackbody model with an innermost disk temperature of 1.2–1.3 keV, and becomes flatter as the source becomes brighter. Hence, X-2 is interpreted to be in a slim-disk state. These results suggest that the two ULXs have black hole masses of some dozens to a few hundred of solar masses.

著者

Toyama Takuji Hoshizaki Hiroshi Isobe Naoki Adachi Hitoshi Naito Shigeto Oshima Shigeru Taniguchi Koichi

出版者

社団法人日本循環器学会

雑誌

Japanese circulation journal (ISSN:00471828)

巻号頁・発行日

vol.64, no.12, pp.937-942, 2000-11-20

被引用文献数

6 6

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To identify and quantify the amount of viable hibernating myocardium in patients with chronic coronary artery disease, resting ^<201>Tl single photon emission computed tomography(SPECT) was compared with ^<99m>Tc-methoxy-isobutyl isonitrile(MIBI) SPECT after nitrate infusion (nitrate-^<99m>Tc-MIBI) and ^<201>Tl SPECT after ^<201>Tl with glucose-insulin-potassium infusion (^<201>Tl-GIK) in 25 patients. Twenty-one patients also underwent completely left ventriculography beforehand and 5±4 months afterwards. SPECT images were divided into 9 segments and scored visually from 0 (normal uptake) to 3 (absent). The defect score was calculated as the summation of the total scores(TDS) in each patient. The TDS of nitrate-^<99m>Tc-MIBI images (6.3±4.3) and ^<201>Tl-GIK images (5.8±4.2) were significantly lower than the 7.4±4.3 of resting ^<201>Tl images (p<0.01). Based on the improvement of wall motion after coronary revascularization, the sensitivity of ^<201>Tl-GIK imaging (85%) was significantly higher (p<0.05), and that of nitrate-^<99m>Tc-MIBI imaging (79%) also tended to be higher (p=0.08), than that of ^<201>Tl imaging (62%) in detecting viable myocardium. The specificity of the 3 methods was almost the same. The nitrate-^<99m>Tc-MIBI and ^<201>Tl-GIK methods were more useful than the resting ^<201>Tl method for evaluating viable hibernating myocardium. Furthermore, the ^<201>Tl-GIK method may provide a more accurate estimate of the amount of viable myocardium than the nitrate-^<99m>Tc-MIBI method.