Optical reference geometry of KerrNewman spacetimes
Abstract
Properties of the optical reference geometry related to KerrNewman blackhole and nakedsingularity spacetimes are illustrated using embedding diagrams of their equatorial plane. It is shown that among all inertial forces defined within the framework of the optical geometry, just the centrifugal force plays a fundamental role in connection with the embedding diagrams because it changes sign at the turning points of the diagrams. The embedding diagrams do not cover the stationary part of the KerrNewman spacetimes completely. Hence, the limits of embeddability are given, and it is established which of the photon circular orbits hosted by the KerrNewman spacetimes appear in the embeddable regions. Some typical embedding diagrams are constructed, and the KerrNewman backgrounds are classified according to the number of embeddable regions of the optical geometry as well as the number of their turning points. It is shown that embedding diagrams are closely related to the notion of the radius of gyration which is useful for analysing a fluid rotating in strong gravitational fields.
 Publication:

Classical and Quantum Gravity
 Pub Date:
 July 2000
 DOI:
 10.1088/02649381/17/14/307
 arXiv:
 arXiv:0803.2533
 Bibcode:
 2000CQGra..17.2691S
 Keywords:

 General Relativity and Quantum Cosmology
 EPrint:
 28 pages, 17 figures