Open AccessEVOLUTION OF ANGULAR VELOCITY OF CENTRAL BLACK HOLES OF ACCRETION DISKS
Author(s) -
Ding-Xiong Wang
Publication year - 1999
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.48.1556
Subject(s) - angular momentum , physics , dimensionless quantity , accretion (finance) , angular velocity , accretion disc , astrophysics , rotating black hole , specific relative angular momentum , total angular momentum quantum number , spinning , black hole (networking) , angular momentum coupling , classical mechanics , mechanics , mechanical engineering , computer network , routing protocol , routing (electronic design automation) , computer science , link state routing protocol , engineering
The evolution characters of angular velocity Ωh 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 Ωh 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, Ωh increases at first, and then decreases in a prograde accretion process. Therefore there exists a maximum of Ωh. 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 Ωh.