标题： 非奇异黑洞在共形引力中的参数估计利用来自NGC 4258的巨脉泽观测数据 显示英文标题

标题： Parameter estimation of nonsingular black holes in conformal gravity using megamaser observational data from NGC 4258

摘要： 在本文中，我们进行贝叶斯统计拟合，通过利用NGC 4258活动星系核中心超大质量黑洞的megamaser天体物理数据，估计共形引力中非奇点黑洞的自由参数。 这种估计是通过考虑一种广义相对论方法进行的，该方法利用了光子源在天空中的位置以及围绕黑洞做圆周运动的水megamaser系统的频率偏移观测数据。 在共形引力框架内，消除施瓦茨希尔德时空在r=0处奇点的一种方法是引入一个由长度尺度参数l和整数参数N表征的共形因子。因此，时空几何取决于黑洞的质量以及共形引力参数l和N。在本工作中，我们对整数参数N=1,2的固定值，估计了质量与距离比M/D和长度尺度比l/D。 这种方法导致所有参数的后验高斯分布，从而得到了长度尺度参数l的最可能值，这与之前基于X射线天体物理数据提取的信息相反，在那里已经建立了参数l的上限。 此外，我们获得了关于此非奇点时空存在ISCO半径的新物理特性。 显示英文摘要

摘要： In this paper, we perform a Bayesian statistical fit to estimate the free parameters of a nonsingular black hole in conformal gravity by employing megamaser astrophysical data of the supermassive black hole hosted at the center of the active galactic nucleus of NGC 4258. This estimation has been carried out by taking into account a general relativistic approach, which makes use of the positions on the sky of the photon sources and the frequency shift observations from the water megamaser system in circular motion around the black hole. Within the framework of conformal gravity, a way to eliminate the singularity at r=0 from the Schwarzschild spacetime is by introducing a conformal factor characterized by a length scale parameter l and an integer parameter N. Therefore, the spacetime geometry depends on the mass of the black hole, and the conformal gravity parameters l and N. In this work, we estimate the mass-to-distance ratio M/D and the length scale ratio l/D for fixed values of the integer parameter N=1,2. This method leads to posterior Gaussian distribution for all the parameters, thus obtaining a most probable value for the length scale parameter l, in contrast to the information extracted from previous constraints based on X-ray astrophysical data, where an upper bound for the parameter l has been established. Furthermore, we obtain new physical properties regarding the existence of the ISCO radius for this nonsingular spacetime.