A Hidden Friend for the Galactic Center Black Hole, Sgr A*
A Hidden Friend for the Galactic Center Black Hole, Sgr A*
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DOI：
10.3847/2041-8213/ab5e3b
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发表时间：
2019-12
期刊：
影响因子：
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通讯作者：
S. Naoz;C. Will;E. Ramirez-Ruiz;A. Hees;A. Ghez;T. Do
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作者：
S. Naoz;C. Will;E. Ramirez-Ruiz;A. Hees;A. Ghez;T. Do
星系形成的等级性质表明，我们的银河系中心可能存在超大质量黑洞双星。我们提出了一种新的方法来约束可能的轨道配置这样一个双同伴银河系中心黑洞人马座A*（Sgr A*）通过测量恒星轨道。专注于星星S 0 -2，我们表明，需要它的轨道稳定性的存在下，一个同伴的Sgr A* 产生严格的限制，这样一个同伴的可能配置。此外，我们表明，精确测量的时间变化的轨道参数的S 0 -2可以产生更强的约束。使用现有的数据S 0 -2，我们推导出上限的双黑洞分离的伴侣质量的函数。对于圆形轨道的情况，我们可以排除半长轴大于170 Au或0.8 mpc的105 M的伴星。这已经比从Sgr A* 的自行研究中获得的界限更严格。包括绕银河系中心运行的其他恒星应该会产生更强的约束，这可能有助于发现Sgr A* 伴星的存在。我们发现，一个同伴也可以影响吸积过程，导致的变化，可能是一致的测量红外耀斑的时间尺度和振幅。最后，如果这样的伴星存在，它将发射引力波辐射，可能被激光干涉仪空间天线（丽莎）探测到。
The hierarchical nature of galaxy formation suggests that a supermassive black hole binary could exist in our galactic center. We propose a new approach to constraining the possible orbital configuration of such a binary companion to the galactic center black hole Sagittarius A* (Sgr A*) through the measurement of stellar orbits. Focusing on the star S0–2, we show that requiring its orbital stability in the presence of a companion to Sgr A* yields stringent constraints on the possible configurations of such a companion. Furthermore, we show that precise measurements of time variations in the orbital parameters of S0–2 could yield stronger constraints. Using existing data on S0–2 we derive upper limits on the binary black hole separation as a function of the companion mass. For the case of a circular orbit, we can rule out a 105 M⊙ companion with a semimajor axis greater than 170 au or 0.8 mpc. This is already more stringent than bounds obtained from studies of the proper motion of Sgr A*. Including other stars orbiting the galactic center should yield stronger constraints that could help uncover the presence of a companion to Sgr A*. We show that a companion can also affect the accretion process, resulting in a variability that may be consistent with the measured infrared flaring timescales and amplitudes. Finally, if such a companion exists, it will emit gravitational wave radiation, potentially detectable with the Laser Interferometer Space Antenna (LISA).