Suzaku observation of two ultraluminous X-ray sources in NGC 1313
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ID | 20651 |
本文ファイル | |
著者 |
Miyawaki, Ryohei
Ebisawa, Ken
Kubota, Aya
Miyamoto, Masao
Winter, Lisa M.
Ueda, Yoshihiro
Dewangan, Gulab C.
Done, Chris
Griffiths, Richard E.
Haba, Yoshito
Kokubun, Motohide
Kotoku, Jun'ichi
Makishima, Kazuo
Matsushita, Kyoko
Mushotzky, Ricard F.
Namiki, Masaaki
Petre, Robert
Tamagawa, Toru
Terashima, Yuichi
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キーワード | accretion, accretion disks
black hole physics
X-rays: individual (NGC 1313 X-1, NGC 1313 X-2)
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NDC |
天文学・宇宙科学
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抄録(英) | 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.
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掲載誌名 |
Publications of the Astronomical Society of Japan
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巻 | 59巻
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開始ページ | S257
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終了ページ | S267
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出版年月日 | 2007-01-25
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出版者 | 日本天文学会
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ISSN | 0004-6264
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NCID | |
言語 |
英語
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NII資源タイプ |
学術雑誌論文
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広大資料タイプ |
学術雑誌論文
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DCMIタイプ | text
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フォーマット | application/pdf
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著者版フラグ | publisher
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権利情報 | Copyright (c) 2007 Astronomical Society of Japan
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関連情報URL | |
部局名 |
理学研究科
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