黑洞自转角速度的演化特征

在同时考虑吸积和Blandford-Znajek过程的条件下，详细讨论了吸积盘（包括薄盘和厚盘）中心黑洞的自转角速度Ω_h的演化特征.结果表明，当黑洞的无量纲角动量a_*演化到某一临界时，Ω_h对时间的变化率由正变负，从而推断在顺行吸积过程事Ω_h先增后减，演化非单调，因而存在一个极大值.并指出黑洞的无量纲角动理a_*比黑洞的角动量J和自转角速度Ω_h更适合描写吸积盘中心黑洞自转状态的演关键词：

EVOLUTION OF ANGULAR VELOCITY OF CENTRAL BLACK HOLES OF ACCRETION DISKS

The evolution characters of angular velocity Ω_h of central black holes of accretion disks (including thin and thick disks) are investigated by considering both accretion and the Blandford-Znajek (BZ) process. It is shown that the rate of change of Ω_h with respect to time truns from the positive value to the negative, as the dimensionless angular momentum a_* evolves to a critical value. Evolving in a non-monotonous way, Ω_h increases at first, and then decreases in a prograde accretion process. Therefore there exists a maximum of Ω_h. It is pointed out that dimensionless angular momentum a_* is more appropriate to describe the spinning state of a central black hole of an accretion disk than angular momentum J and angular velocity Ω_h.