Subaru和Gemini对SS 433的观测：对致密天体质量的新约束
Subaru and Gemini Observations of SS 433: New Constraint on the Mass of the Compact Object
摘要：
我们目前的光谱观测结果的质量施主星在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。Subaru/FOCAS在2007年10月6-8日和10日进行了观测，覆盖轨道相位φ =0.96-0.26。我们首先计算了这些光谱与参考星HD 9233在4740-4840埃波长范围内的交叉关联函数。选择该区域以避免伴随污染发射分量的“强”吸收线。Hillwig & Gies（2008）将相同的分析应用于在phi=0.84-0.30时采集的Gemini/GMOS存档数据。根据Subaru和Gemini CCF的观测结果，施主星径向速度曲线的振幅为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，我们得到施主星和致密天体的质量分别为M_O=12.4+/-1.9 M_sun和M_X=4.3+/-0.6 M_sun。然而，我们的结论是，这些值应被视为上限。通过对斯巴鲁观测到的强线和弱线的平均吸收线轮廓的分析，我们发现了致密天体加热效应的证据。使用一个简单的模型，我们发现，真正的径向速度振幅的施主星可以低至40+/-5公里s-1，以产生所观察到的吸收线的轮廓。考虑到施主星的加热作用，导出的质量可降低到M_O=10.4 + 2.3/-1.9 M_sun和M_X=2.5 + 0.7/-0.6 M_sun。我们的最终约束，1.9 M_sun< M_X <4.9 M_sun，表明SS 433中的致密物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的可能性。
英文摘要：
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/FOCAS observations were performed on October 6-8 and 10, 2007, covering the orbital phase of phi=0.96-0.26. We first calculate cross correlation function of these spectra with that of the reference star HD 9233 in the wavelength range of 4740-4840 Angstrom. This region is selected to avoid 'strong' absorption lines accompanied with contaminating emission components. The same analysis is applied to archive data of Gemini/GMOS taken at phi=0.84-0.30 by Hillwig & Gies (2008). From the Subaru and Gemini CCF results, the amplitude of 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 M_O=12.4+/-1.9 M_sun and M_X=4.3+/-0.6 M_sun, 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 and weak lines 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 M_O=10.4 +2.3/-1.9 M_sun and M_X=2.5 +0.7/-0.6 M_sun. Our final constraint, 1.9 M_sun< M_X <4.9 M_sun, 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.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
