Suzaku observation of the symbiotic X-ray binary IGR J16194-2810
Suzaku observation of the symbiotic X-ray binary IGR J16194-2810
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DOI：
10.1093/pasj/pst001
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发表时间：
2013-08
影响因子：
2.3
通讯作者：
Y. Kitamura;H. Takahashi;Y. Fukazawa
中科院分区：
文献类型：
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作者：
Y. Kitamura;H. Takahashi;Y. Fukazawa
我们于2009年利用铃鹿X射线卫星观测到IGR J16194-2810处于低/硬状态。源是一个共生X射线双星(SyXB)，被归类为低质量X射线双星(LMXB)，因为该系统由M型巨星和可能的中子星(NS)组成。我们用XIS和HXD-PIN探测了0.8-50keV的信号。2-10keV的光度为L~7x10^34erg S^-1，相当于~10^-3的L_Edd，其中L_Edd是1.4M_o NS的爱丁顿光度，假定源距离为3.7kpc。光度与过去的观测结果相似。光谱分析表明，在~2keV以下和以上有两个发射分量。硬发射分量用康普顿化黑体发射模型表示，种子光子温度~1.0keV，发射半径~700m，种子光子来自NS表面的一小部分。软成分是由原始黑体(~0.4keV，~1.7公里)或康普顿发射(~0.1keV，~75公里)复制的。我们认为它的来源是南北面其他部分或吸积流的排放。比较了IGR J16194-2810与SyXB(4U 1700+24)和LMXB(Aql X-1和4U 0614+091)硬发射分量的物理参数。这一比较表明，这些处于低/硬态的SyXB在NS表面上具有较小的辐射区(~lt；1公里)，而种子光子温度(~1keV)高于比较的LMXB。
We observed IGR J16194-2810 in the low/hard state with the Suzaku X-ray satellite in 2009. The source is a Symbiotic X-ray Binary (SyXB) classified as a category of a Low-Mass X-ray Binary (LMXB), since the system is composed of an M-type giant and probably a neutron star (NS). We detected the 0.8-50 keV signal with the XIS and HXD-PIN. The 2-10 keV luminosity was L ~ 7 x 10^34 erg s^-1 corresponding to ~10^-3 L_Edd, where L_Edd is the Eddington Luminosity of a 1.4 M_o NS and a source distance of 3.7 kpc is assumed. The luminosity is similar to those of past observations. The spectral analysis showed that there are two emission components below and above ~2 keV. The hard emission component is represented by a Comptonized black-body emission model with the seed-photon temperature ~1.0 keV and the emission radius ~700 m. The seed photon is considered to come from a small fraction of the NS surface. The soft component is reproduced by either a raw black-body (~0.4 keV, ~1.7 km) or a Comptonized emission (~0.1 keV, ~75 km). We think the origin is the emission from other part of the NS surface or the accreting stream. The physical parameters of the hard emission component of IGR J16194-2810 are compared with those of an SyXB (4U 1700+24) and LMXBs (Aql X-1 and 4U 0614+091). This comparison reveals that these SyXBs in the low/hard state have a smaller radiation region (< 1 km) on the NS surface with a higher seed-photon temperature (~1 keV) than the compared LMXBs.