A Spectral Study of the Black Hole Candidate XTE J1752-223 in the High/Soft State with MAXI, Suzaku and Swift
A Spectral Study of the Black Hole Candidate XTE J1752-223 in the High/Soft State with MAXI, Suzaku and Swift
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DOI：
10.1093/pasj/64.1.13
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发表时间：
2011-09
期刊：
影响因子：
--
通讯作者：
S. Nakahira;S. Koyama;Y. Ueda;K. Yamaoka;M. Sugizaki;T. Mihara;M. Matsuoka;A. Yoshida;K. Makishi
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文献类型：
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作者：
S. Nakahira;S. Koyama;Y. Ueda;K. Yamaoka;M. Sugizaki;T. Mihara;M. Matsuoka;A. Yoshida;K. Makishi
我们报告了2009- 2010年爆发的候选黑洞XTE J1752—223的x射线光谱分析，利用MAXI/气体狭缝相机（GSC）， Swift/XRT和Suzaku获得的数据，它们互补工作。正如Nakahira et al.（2010）已经报道的那样，MAXI在整个爆发过程中连续监测了大约8个月的源头。持续2个月的MAXI/GSC高/软态能谱都可以用多色盘加幂律模型很好地表示。最内层盘温度从$\sim$ 0.7 keV下降到$\sim$ 0.4 keV，盘通量下降了一个数量级。然而，最里面的半径是恒定的$\sim$ 41 $D_{3.5}(\cos{\it i})^{-1/2}$ km，其中$D_{3.5}$是3.5 kpc单位的源距离，$i$是倾角。MAXI/GSC获得的多色磁盘参数与Swift/XRT和Suzaku一致。朱雀的数据也表明了一种可能性，即圆盘的发射有轻微的复杂性，这可以解释之前报道的广泛的铁- k特征。假设得到的最内层半径代表非旋转黑洞的最内层稳定圆轨道，我们估计黑洞的质量为5.51 $\pm$ 0.28 $M_{\odot}$$D_{3.5}(\cos{\it i})^{-1/2}$，其中考虑了对无应力内边界条件的修正和1.7的颜色硬化因子。如果根据瞬态喷流的无线电监测表明倾角小于49 $^{\circ}$，那么2010年4月的软-硬转变发生在1—4% of Eddignton luminosity, the fitting of the Suzaku spectra with a relativistic accretion-disk model derives constraints on the mass and the distance to be 3.1--55 $M_{\odot}$ and 2.3--22 {\rm kpc}, respectively. This confirms that the compact object in XTE J1752--223 is a black hole.
We report on the X-ray spectral analysis of the black hole candidate XTE\ J1752--223 in the 2009--2010 outburst, utilizing data obtained with the MAXI/Gas Slit Camera (GSC), the Swift/XRT, and Suzaku, which work complementarily. As already reported by Nakahira et al. (2010) MAXI monitored the source continuously throughout the entire outburst for about eight months. All the MAXI/GSC energy spectra in the high/soft state lasting for 2 months are well represented by a multi-color disk plus power-law model. The innermost disk temperature changed from $\sim$0.7 keV to $\sim$0.4 keV and the disk flux decreased by an order of magnitude. Nevertheless, the innermost radius is constant at $\sim$41 $D_{3.5}(\cos{\it i})^{-1/2}$ km, where $D_{3.5}$ is the source distance in units of 3.5 kpc and $i$ the inclination. The multi-color disk parameters obtained with the MAXI/GSC are consistent with those with the Swift/XRT and Suzaku. The Suzaku data also suggests a possibility that the disk emission is slightly Comptonized, which could account for broad iron-K features reported previously. Assuming that the obtained innermost radius represents the innermost stable circular orbit for a non-rotating black hole, we estimate the mass of the black hole to be 5.51$\pm$0.28 $M_{\odot}$ $D_{3.5}(\cos{\it i})^{-1/2}$, where the correction for the stress-free inner boundary condition and color hardening factor of 1.7 are taken into account. If the inclination is less than 49$^{\circ}$ as suggested from the radio monitoring of transient jets and the soft-to-hard transition in 2010 April occurred at 1--4% of Eddignton luminosity, the fitting of the Suzaku spectra with a relativistic accretion-disk model derives constraints on the mass and the distance to be 3.1--55 $M_{\odot}$ and 2.3--22 {\rm kpc}, respectively. This confirms that the compact object in XTE J1752--223 is a black hole.