论文标题
重力波背景和脉冲星阵列的手性
Chirality of the gravitational-wave background and pulsar-timing arrays
论文作者
论文摘要
我们描述了用脉冲星定位阵列获得的定时残差的圆极化重力波背景的特征。最普遍地，圆极化将取决于重力波的方向，我们在球形谐波方面描述了这种角度依赖性。虽然无法检测到单极的幅度（重力波背景的总体手性），但在理论上可以想象各向异性的度量。我们为循环极化各向异性的最小变化估计器提供表达式。我们评估了最小的可检测信号，这是检测到各向同性GW信号的信噪比的函数，并且在调查中检测到脉冲星数（假定大致均匀分布在天空中）。我们发现，如果它们的振幅接近最大，并且一旦以信号 - 噪声比率$ \ gtrsim400 $，则可以在$ \ gtrsim100 $ pulsars的调查中检测到圆极化的总偶极子和较高的总多物。不过，即使可以建立各向异性，有关其方向的信息也有限。类似的论点适用于对重力波的天文搜索。
We describe the signatures of a circularly polarized gravitational-wave background on the timing residuals obtained with pulsar-timing arrays. Most generally, the circular polarization will depend on the gravitational-wave direction, and we describe this angular dependence in terms of spherical harmonics. While the amplitude of the monopole (the overall chirality of the gravitational-wave background) cannot be detected, measures of the anisotropy are theoretically conceivable. We provide expressions for the minimum-variance estimators for the circular-polarization anisotropy. We evaluate the smallest detectable signal as a function of the signal-to-noise ratio with which the isotropic GW signal is detected and the number of pulsars (assumed to be roughly uniformly spread throughout the sky) in the survey. We find that the overall dipole of the circular polarization and a few higher overall multipoles, are detectable in a survey with $\gtrsim100$ pulsars if their amplitude is close to maximal and once the isotropic signal is established with a signal-to-noise ratio $\gtrsim400$. Even if the anisotropy can be established, though, there will be limited information on its direction. Similar arguments apply to astrometric searches for gravitational waves.
