论文标题
均匀密度恒星轴向重力扰动的回声
Echoes of axial gravitational perturbations in stars of uniform density
论文作者
论文摘要
这项工作研究了紧凑物体中轴向重力扰动中的回声。为此，我们提出了在两个坐标系中实现的有限差方法的替代方案，其中初始条件放在乌龟坐标的轴上，并具有适当的边界条件，完全尊重因果关系。然后使用该方案研究Schwarzschild黑洞和均匀密度恒星中准振荡的时间分布。当在二维演化曲线中呈现时，随着初始扰动的进化并与有效电位的峰碰撞，黑洞度量标准中所得的环形波形被分为反射和透射波。另一方面，对于紧凑的恒星，准振荡可能以回声为特征。与因果关系一致，该现象是由于引力波在恒星中心的发散电位与有效电位的峰值之间弹跳而产生的。还讨论了本研究的含义。
This work investigates the echoes in axial gravitational perturbations in compact objects. To this end, we propose an alternative scheme of the finite difference method implemented in two coordinate systems, where the initial conditions are placed on the axis of the tortoise coordinate with appropriate boundary conditions that fully respect the causality. The scheme is then employed to study the temporal profiles of the quasinormal oscillations in the Schwarzschild black hole and the uniform-density stars. When presented in a two-dimensional evolution profile, the resulting ringdown waveforms in the black hole metric are split into the reflected and transmitted waves as the initial perturbations evolve and collide with the peak of the effective potential. On the other hand, for compact stars, quasinormal oscillations might be characterized by echoes. Consistent with the causality arguments, the phenomenon is produced by the gravitational waves bouncing between the divergent potential at the star's center and the peak of the effective potential. The implications of the present study are also discussed.
