The Zoo of X-Ray Sources in the Galactic Center Region: Observations with BeppoSAX
The Zoo of X-Ray Sources in the Galactic Center Region: Observations with BeppoSAX
复制标题
银河系中心区域的 X 射线源动物园：BeppoSAX 观测
DOI：
10.1086/307887
复制
发表时间：
1999
期刊：
影响因子：
--
通讯作者：
M. Orlandini
中科院分区：
文献类型：
--
作者：
L. Sidoli;S. Mereghetti;G. Israel;L. Chiappetti;A. Treves;M. Orlandini
我们报告了用BeppoSAX卫星对银河系中心区域（α l θ < 2°，α B θ < 0. 5 °）进行的一次巡天的结果。来自银河系中心的通量对应于2-10 keV范围内的~3 × 1035 ergs-1的光度。由于有限的角分辨率（101“），只有一部分应该来自人马座A*，这是一个非热射电源，被认为标志着银河系的动力中心。除了漫射发射，（LX 1036尔格s-1）点源已被观测到，（A1742-294、SLX 1744-299、SLX 1744-300、1 E 1743.1-2843、1 E 1740.7-2942）和瞬态（XTE J1748-288、SAX J1747.0-2853和KS 1741-293）。低质量X射线双星AX J1745.6-2901是在1997年8月被发现的，它与Sgr A* 的距离仅为1.′3。硬X射线源1 E 1740.7-2942的1-150 keV光谱可以用康普顿化模型很好地描述，这是黑洞候选者在低/硬状态下的典型特征，没有强Fe线的证据。对I型爆发的探测表明，瞬态源SAXJ1747.0 -2853（可能与1976年的瞬态GX 0.2-0.2相同）是一个含有中子星星的LMXRB。瞬态黑洞候选者XTE J1748-288的光度（~1036尔格·秒-1）与XTE全天监测仪观测到的爆发指数衰减的外推一致。两个较暗的源极有可能与年轻的中子星有关：位于复合超新星遗迹G0.9+0.1中心的X射线源（可能是弥散的），以及轴对称射电源G359.23-0.92的“头部”。后者已被检测到以上~6千电子伏，支持非热发射机制。
We report the results of a survey of the Galactic center region (∣ l ∣ < 2°, ∣ b ∣ < 0.°5) performed with the BeppoSAX satellite. The flux from the center of our Galaxy corresponds to a luminosity of ~3 × 1035 ergs s-1 in the 2-10 keV range. Due to the limited angular resolution (≳1'), only part of it is supposed to come from Sagittarius A*, the nonthermal radio source that is believed to mark the dynamical center of the Galaxy. In addition to the diffuse emission, several bright (LX ≳ 1036 ergs s-1) point sources have been observed, both persistent (A1742-294, SLX 1744-299, SLX 1744-300, 1E 1743.1-2843, 1E 1740.7-2942) and transient (XTE J1748-288, SAX J1747.0-2853 and KS 1741-293). The low-mass X-ray binary (LMXRB) AX J1745.6-2901, discovered with ASCA at only 1.′3 from Sgr A*, was detected in a low-luminosity state in 1997 August. The 1-150 keV spectrum of the hard X-ray source 1E 1740.7-2942 is well described by a Comptonization model, typical of black hole candidates in their low/hard state, with no evidence for strong Fe lines. The detection of a type I burst shows that the transient source SAX J1747.0-2853 (probably the same as the 1976 transient GX 0.2-0.2) is a LMXRB containing a neutron star. The transient black hole candidate XTE J1748-288 was detected at a luminosity (~1036 ergs s-1) consistent with the extrapolation of the exponential decay of the outburst observed with the XTE All-Sky Monitor. Two fainter sources are very likely associated with young neutron stars: the (possibly diffuse) X-ray source at the center of the composite supernova remnant G0.9+0.1, and the "head" of the axially symmetric radio source G359.23-0.92. The latter has been detected above ~6 keV, supporting a nonthermal emission mechanism.