Dynamical Evidence for a Black Hole in the Microquasar XTE J1550–564
Dynamical Evidence for a Black Hole in the Microquasar XTE J1550–564
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DOI：
10.1086/338984
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发表时间：
2001-12
期刊：
影响因子：
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通讯作者：
J. Orosz;P. Groot;M. van der Klis;J. McClintock;Michael R. Garcia;P. Zhao;R. Jain;C. Bailyn;
中科院分区：
文献类型：
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作者：
J. Orosz;P. Groot;M. van der Klis;J. McClintock;Michael R. Garcia;P. Zhao;R. Jain;C. Bailyn;
对XTE J1550-564微类星体系统伴星（G8 IV ~ K4 III型）的光谱观测显示，其径向速度曲线的最佳拟合光谱周期为Psp = 1.552±0.010天，半振幅为K2 = 349±12 km s-1。光学质量函数为f(M) = 6.86±0.71 M☉（1 σ）。我们暂时测量伴星的旋转速度为Vrot sin i = 90±10 km s-1，从表面上看，这意味着质量比Q≡M1/M2 = 6.6 (1 σ)，使用上面的K2值。通过对椭球面光和径向速度曲线的同时建模，推导出二元参数的约束条件。光度周期（1.5430天≤Pph≤1.5440天）、k -速度（350.2≤K2≤368.6 km s-1）、倾角(67。°0≤I≤77。°4)、质量比（Q≥12.0）和轨道间距（11.55 R☉≤a≤12.50 R☉）。在这些几何约束下，我们发现这个致密天体最可能的质量值是9.41 M☉，其1 σ范围为8.36 M☉≤M1≤10.76 M☉。如果我们在椭球体模型中使用我们的临时值Vrot sin i = 90±10 km s-1作为附加约束，我们发现光度周期的1 σ范围为1.5432天≤Pph≤1.5441天，k -速度的1 σ范围为352.2≤K2≤370.1 km s-1, 70。°8≤I≤75。倾角为°4，质量比为6.7≤Q≤11.0，轨道间距为12.35 R☉≤a≤13.22 R☉。这些几何约束暗示最可能的致密天体质量值为10.56 M☉，1 σ范围为9.68 M☉≤M1≤11.58 M☉。在任何一种情况下，致密天体的质量都远远超过稳定中子星的最大质量，因此我们得出结论，XTE J1550-564包含一个黑洞。
Optical spectroscopic observations of the companion star (type G8 IV to K4 III) in the microquasar system XTE J1550-564 reveal a radial velocity curve with a best-fitting spectroscopic period of Psp = 1.552 ± 0.010 days and a semiamplitude of K2 = 349 ± 12 km s-1. The optical mass function is f(M) = 6.86 ± 0.71 M☉ (1 σ). We tentatively measure the rotational velocity of the companion star to be Vrot sin i = 90 ± 10 km s-1, which when taken at face value implies a mass ratio of Q ≡ M1/M2 = 6.6 (1 σ), using the above value of K2. We derive constraints on the binary parameters from simultaneous modeling of the ellipsoidal light and radial velocity curves. We find 1 σ ranges for the photometric period (1.5430 days ≤ Pph ≤ 1.5440 days), K-velocity (350.2 ≤ K2 ≤ 368.6 km s-1), inclination (67.°0 ≤ i ≤ 77.°4), mass ratio (Q ≥ 12.0), and orbital separation (11.55 R☉ ≤ a ≤ 12.50 R☉). Given these geometrical constraints, we find that the most likely value of the mass of the compact object is 9.41 M☉ with a 1 σ range of 8.36 M☉ ≤ M1 ≤ 10.76 M☉. If we apply our tentative value of Vrot sin i = 90 ± 10 km s-1 as an additional constraint in the ellipsoidal modeling, we find 1 σ ranges of 1.5432 days ≤ Pph ≤ 1.5441 days for the photometric period, 352.2 ≤ K2 ≤ 370.1 km s-1 for the K-velocity, 70.°8 ≤ i ≤ 75.°4 for the inclination, 6.7 ≤ Q ≤ 11.0 for the mass ratio, and 12.35 R☉ ≤ a ≤ 13.22 R☉ for the orbital separation. These geometrical constraints imply the most likely value of the mass of the compact object of 10.56 M☉ with a 1 σ range of 9.68 M☉ ≤ M1 ≤ 11.58 M☉. In either case the mass of the compact object is well above the maximum mass of a stable neutron star, and we therefore conclude that XTE J1550-564 contains a black hole.