SUBARU AND GEMINI OBSERVATIONS OF SS 433: NEW CONSTRAINT ON THE MASS OF THE COMPACT OBJECT
SUBARU AND GEMINI OBSERVATIONS OF SS 433: NEW CONSTRAINT ON THE MASS OF THE COMPACT OBJECT
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DOI：
10.1088/0004-637x/709/2/1374
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发表时间：
2009-12
期刊：
影响因子：
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通讯作者：
K. Kubota;Y. Ueda;S. Fabrika;A. Medvedev;E. Barsukova;O. Sholukhova;V. Goranskij
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文献类型：
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作者：
K. Kubota;Y. Ueda;S. Fabrika;A. Medvedev;E. Barsukova;O. Sholukhova;V. Goranskij
我们目前的光谱观测结果的质量施主星星在SS 433与斯巴鲁和双子座，目的是最好地约束紧凑的对象的质量。斯巴鲁/暗天体照相机和摄谱仪在2007年10月6日至8日和10日的四个晚上进行了观测，覆盖了轨道相位θ = 0.96 − 0.26。我们首先计算了这些光谱与参考星星HD 9233在4740-4840 nm波长范围内的互相关函数。选择这个区域是为了避免“强”吸收线伴随着污染的排放成分，这最有可能源于周围的施主星星，如风和气体流。同样的分析也适用于Hillwig & Gies在θ = 0.84 − 0.30时采集的Gemini/GMOS的存档数据。根据斯巴鲁和双子座CCF的结果，施主星星的径向速度曲线的振幅被确定为58.3 ± 3.8 km s−1，系统速度为59.2 ± 2.5 km s−1。结合致密天体的径向速度曲线，我们得到施主星星和致密天体的质量分别为MO = 12.4 ± 1.9 M和MX = 4.3 ± 0.6 M。然而，我们的结论是，这些值应被视为上限。从斯巴鲁观测到的强线（主要是离子）和弱线（主要是中性粒子）的平均吸收线轮廓的分析中，我们发现了来自紧凑物体的加热效应的证据。使用一个简单的模型，我们发现施主星星的真实径向速度振幅可以低至40 ± 5 km s−1，以产生观测到的吸收线轮廓。考虑到施主星星的加热，可以将导出的质量降低到MO = 10.4+2.3−1.9 M，MX = 2.5+0.7−0.6 M。我们的最后一个约束，1.9 M的引力矩MX = 4.9 M的引力矩，表明SS 433中的致密天体很可能是一个低质量黑洞，尽管不能完全排除大质量中子星星的可能性。
We present results of optical spectroscopic observations of the mass donor star in SS 433 with Subaru and Gemini, with an aim to best constrain the mass of the compact object. Subaru/Faint Object Camera and Spectrograph observations were performed on four nights of 2007 October 6–8 and 10, covering the orbital phase of ϕ = 0.96 − 0.26. We first calculate the cross-correlation function (CCF) of these spectra with that of the reference star HD 9233 in the wavelength range of 4740–4840 Å. This region is selected to avoid “strong” absorption lines accompanied with contaminating emission components, which most probably originate from the surroundings of the donor star, such as the wind and gas stream. The same analysis is applied to archive data of Gemini/GMOS taken at ϕ = 0.84 − 0.30 by Hillwig & Gies. From the Subaru and Gemini CCF results, the amplitude of the radial velocity curve of the donor star is determined to be 58.3 ± 3.8 km s−1 with a systemic velocity of 59.2 ± 2.5 km s−1. Together with the radial velocity curve of the compact object, we derive the mass of the donor star and compact object to be MO = 12.4 ± 1.9 M☉ and MX = 4.3 ± 0.6 M☉, respectively. We conclude, however, that these values should be taken as upper limits. From the analysis of the averaged absorption line profiles of strong lines (mostly ions) and weak lines (mostly neutrals) observed with Subaru, we find evidence for heating effects from the compact object. Using a simple model, we find that the true radial velocity amplitude of the donor star could be as low as 40 ± 5 km s−1 in order to produce the observed absorption-line profiles. Taking into account the heating of the donor star may lower the derived masses to MO = 10.4+2.3−1.9 M☉ and MX = 2.5+0.7−0.6 M☉. Our final constraint, 1.9 M☉ ⩽MX⩽ 4.9 M☉, indicates that the compact object in SS 433 is most likely a low mass black hole, although the possibility of a massive neutron star cannot be firmly excluded.