Suzaku observation of two ultraluminous X-ray sources in NGC 1313
Suzaku observation of two ultraluminous X-ray sources in NGC 1313
复制标题
DOI：
10.1143/ptps.169.229
复制
发表时间：
2006-10
影响因子：
2.3
通讯作者：
T. Mizuno;R. Miyawaki;K. Ebisawa;A. Kubota;M. Miyamoto;L. Winter;Y. Ueda;N. Isobe;G. Dewangan;C. Done;R. Griffiths;Y. Haba;M. Kokubun;J. Kotoku;K. Makishima;K. Matsushita;R. Mushotzky;M. Namiki;R. Petre;H. Takahashi;T. Tamagawa;Y. Terashima
中科院分区：
文献类型：
--
作者：
T. Mizuno;R. Miyawaki;K. Ebisawa;A. Kubota;M. Miyamoto;L. Winter;Y. Ueda;N. Isobe;G. Dewangan;C. Done;R. Griffiths;Y. Haba;M. Kokubun;J. Kotoku;K. Makishima;K. Matsushita;R. Mushotzky;M. Namiki;R. Petre;H. Takahashi;T. Tamagawa;Y. Terashima
使用来自日本第五颗 X 射线卫星朱雀的数据，对附近正面的晚型 Sb 星系 NGC 1313 中的两个超发光 X 射线源 (ULX) 进行了研究。在 90 ks 观测中，名为 X-1 和 X-2 的源均表现出约 50% 的密度变化。 X-1和X-2的0.4-10 keV X射线光度测量结果分别为2.5 x lo4' erg s-'和5.8 x erg s-I，需要50-20011/1的黑洞，才能不超过Eddingtion极限。对于 X-1：光谱表现出具有高能量截止的强幂律分量，这被认为是由盘状日冕的强康普顿化引起的，表明源处于非常高的状态。 X-1 光谱中 7.0 keV 和 7.8 keV 处发现的等效宽度为 40 -80 eV 的吸收线特征支持系统上存在高度电离等离子体和高质量吸积率。发现 NGC 1313 星周物质朝向 X-1 的氧丰度低于太阳，即。 O/H = (1.0 中的 5) x lW4。 X-2 较暗相的光谱最好用 zn = 1.2-1.3 keV 的多色圆盘黑体模型来表示，并且随着通量的增加而变得更平坦；源被解释为处于纤薄磁盘状态。
A study was made of two ultraluminous X-ray sourccs (ULXs) in the nearby face-on, late-type Sb galaxy NGC 1313 using data from Suzaku, the 5th .Japanese X-ray satellite. Within the 90 ks observation, both sources named X-1 and X-2 exhibited hmniinosity change by about 50 %. The 0.4-10 keV X-ray luminosity was measured to be 2.5 x lo4' erg s-' and 5.8 x erg s-I for X-1 and X-2, respectively, requiring a black hole of 50-20011/1, in order not to exceed the Eddingtion limit. For X-1: the spectrum exhibited a strong power-law component with a high energy cutoff which is thought to arise from strong Comptonization by a disk corona, suggesting the source was in a very high state. Absorption line features with equivalent widths of 40 -80 eV found at 7.0 keV and 7.8 keV in the X-1 spectrum support the presence 'of a highly ionized plasma and a high mass accretion rate on the system. Oxygen abundance of the NGC 1313 circumstellar matter toward X-1 was found to be subsolar, viz. O/H = (5.Of 1.0) x lW4. The spectrum of X-2 in fainter phase is best represented by a multicolor disk blackbody model with zn = 1.2-1.3 keV and becomes flatter as the flux increases; the source is intcrpreted to be in a slim disk state.