论文标题
从圆形赤道Kerr轨道机的最大可观察的蓝光
Maximum Observable Blueshift from Circular Equatorial Kerr Orbiters
论文作者
论文摘要
黑洞的事件范围附近的时空区域可以看作是相对于远距离观察者的大型重力红移的深势。但是，该区域中的物质以相对论的速度行驶，并且可以将大量的多普勒转移到其电磁发射，有时会导致无穷大处观察到的净蓝光。因此，黑洞将其附近单色源的线发射扩大到平滑腐烂的“红翼” - 其磁通在大红移处消失 - 与“蓝色刀片”一起，将有限的磁通保持在尖锐的边缘，并与最大可观察的蓝调相对应。在本文中，我们研究了各向同性单色发射器产生的蓝色刀片，在Kerr Black Hole周围的圆形赤道轨道上，并获得了简单的关系，描述了最大蓝光的方式如何编码黑洞的自旋和倾斜度。我们发现，最大蓝光的少量值产生了出色的倾斜度探针，而较大的值则在旋转或倾斜度上提供了强大的限制。这些结果与正在进行的和未来的观察结果直接相关，旨在通过扩大周围线排放的范围来推断超质量黑洞的角度动量。
The region of spacetime near the event horizon of a black hole can be viewed as a deep potential well at large gravitational redshift relative to distant observers. However, matter orbiting in this region travels at relativistic speeds and can impart a significant Doppler shift to its electromagnetic emission, sometimes resulting in a net observed blueshift at infinity. Thus, a black hole broadens the line emission from monochromatic sources in its vicinity into a smoothly decaying "red wing"--whose flux vanishes at large redshift--together with a "blue blade" that retains finite flux up to a sharp edge corresponding to the maximum observable blueshift. In this paper, we study the blue blade produced by isotropic monochromatic emitters on circular equatorial orbits around a Kerr black hole, and obtain simple relations describing how the maximum blueshift encodes black hole spin and inclination. We find that small values of the maximum blueshift yield an excellent probe of inclination, while larger values provide strong constraints on spin or inclination in terms of the other. These results bear direct relevance to ongoing and future observations aiming to infer the angular momentum of supermassive black holes from the broadening of their surrounding line emission.
