arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1007.0007astro-ph.GAgr-qc
收藏

银河系中心星和双星的相对论轨道拟合

Towards relativistic orbit fitting of Galactic center stars and pulsars

Raymond Angelil, Prasenjit Saha, David Merritt

摘要:

围绕银河系中心黑洞运行的S型恒星在近心通过时的速度达到光速的百分之几。例如,这使得近心点的S2比已知的双星更具相对论性,并为测试广义相对论开辟了新的可能性。本文发展了一种技术,用于拟合近开普勒轨道的史瓦西曲率,帧拖动,和自旋引起的扭矩,沿轨道分布的红移测量,但集中在近心附近的扰动。轨道和光路效应都考虑在内。结果表明,不需要静止帧频率的绝对校准。因此,如果发现了与S星轨道相似的脉冲星,这里描述的技术可以不加改变地应用,从而可以利用脉冲星计时的更高精度。例如,一小时内3微秒的脉冲计时相当于30厘米/秒的有效红移精度,足以测量来自S2类轨道的框架拖曳和四极矩,假设可以克服其他质量引起的牛顿“前景”等问题。另一方面,如果发现轨道周期为一个月量级的恒星,那么使用E-ELT的1 km/s水平的恒星光谱也可以实现同样的结果。

英文摘要:

The S stars orbiting the Galactic center black hole reach speeds of up to a few percent the speed of light during pericenter passage. This makes, for example, S2 at pericenter much more relativistic than known binary pulsars, and opens up new possibilities for testing general relativity. This paper develops a technique for fitting nearly-Keplerian orbits with perturbations from Schwarzschild curvature, frame dragging, and spin-induced torque, to redshift measurements distributed along the orbit but concentrated around pericenter. Both orbital and light-path effects are taken into account. It turns out that absolute calibration of rest-frame frequency is not required. Hence, if pulsars on orbits similar to the S stars are discovered, the technique described here can be applied without change, allowing the much greater accuracies of pulsar timing to be taken advantage of. For example, pulse timing of 3 microsec over one hour amounts to an effective redshift precision of 30 cm/s, enough to measure frame dragging and the quadrupole moment from an S2-like orbit, provided problems like the Newtonian "foreground" due to other masses can be overcome. On the other hand, if stars with orbital periods of order a month are discovered, the same could be accomplished with stellar spectroscopy from the E-ELT at the level of 1 km/s.

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。

↑