Pulsar timing in extreme mass ratio binaries: a general relativistic approach
Pulsar timing in extreme mass ratio binaries: a general relativistic approach
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DOI：
10.1093/mnras/stz845
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发表时间：
2019-03
影响因子：
4.8
通讯作者：
T. Kimpson;Kinwah Wu;S. Zane
中科院分区：
文献类型：
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作者：
T. Kimpson;Kinwah Wu;S. Zane
在围绕超大质量或中等质量黑洞的紧密相对论轨道上探测脉冲星（PSR）-例如在银河系中心或球状星团中心-将允许在强场，非线性状态下精确测试广义相对论（GR）。我们提出了一个框架，用于计算从PSR在这样的极端质量比二进制（EMRB）的理论时频信号。这个框架是完全相对论的，没有弱场近似，因此能够解释所有高阶强场引力效应，相对论自旋动力学，与天体物理效应的卷积以及对PSR定时信号的综合影响。具体来说，我们计算的脉冲星无线电信号的时空路径和复杂的轨道和自旋动力学的自旋脉冲星周围的克尔黑洞，占时空曲率和帧拖动，相对论和引力时间延迟，引力光弯曲，时空色散引起的等离子体沿着视线和相对论性畸变的存在。然后，这允许生成一致的时间-频率解决方案。这种框架是评估PSR作为强场GR探针的关键，有助于为检测承载PSR的EMRB系统提供信息，最重要的是，提供准确的理论基础，然后与观测结果进行比较，以测试基础物理。
The detection of a pulsar (PSR) in a tight, relativistic orbit around a supermassive or intermediate mass black hole - such as those in the Galactic centre or in the centre of Globular clusters - would allow for precision tests of general relativity (GR) in the strong-field, non-linear regime. We present a framework for calculating the theoretical time-frequency signal from a PSR in such an Extreme Mass Ratio Binary (EMRB). This framework is entirely relativistic with no weak-field approximations and so able to account for all higher-order strong-field gravitational effects, relativistic spin dynamics, the convolution with astrophysical effects and the combined impact on the PSR timing signal. Specifically we calculate both the spacetime path of the pulsar radio signal and the complex orbital and spin dynamics of a spinning pulsar around a Kerr black hole, accounting for spacetime curvature and frame dragging, relativistic and gravitational time delay, gravitational light bending, temporal and spatial dispersion induced by the presence of plasma along the line of sight and relativistic aberration. This then allows for a consistent time-frequency solution to be generated. Such a framework is key for assessing the use of PSR as probes of strong field GR, helping to inform the detection of an EMRB system hosting a PSR and, most essentially, for providing an accurate theoretical basis to then compare with observations to test fundamental physics.