このエントリーをはてなブックマークに追加
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
キーワード
accretion, accretion disks
black hole physics
X-rays: individual (NGC 1313 X-1, NGC 1313 X-2)
NDC
天文学・宇宙科学
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.
掲載誌名
Publications of the Astronomical Society of Japan
59巻
開始ページ
S257
終了ページ
S267
出版年月日
2007-01-25
出版者
日本天文学会
ISSN
0004-6264
NCID
言語
英語
NII資源タイプ
学術雑誌論文
広大資料タイプ
学術雑誌論文
DCMIタイプ
text
フォーマット
application/pdf
著者版フラグ
publisher
権利情報
Copyright (c) 2007 Astronomical Society of Japan
関連情報URL
部局名
理学研究科