Rigidly rotating zeroangularmomentum observer surfaces in the Kerr spacetime
Abstract
A stationary observer in the Kerr spacetime has zero angular momentum if their angular velocity ω has a particular value, which depends on the position of the observer. Worldlines of such zeroangularmomentum observers (ZAMOs) with the same value of the angular velocity ω form a threedimensional surface, which has the property that the Killing vectors generating time translation and rotation are tangent to it. We call such a surface a rigidly rotating ZAMO surface. This definition allows for a natural generalization to the surfaces inside the black hole, where ZAMO trajectories formally become spacelike. A general property of such a surface is that there exist linear combinations of the Killing vectors with constant coefficients which make them orthogonal on it. In this paper we discuss properties of the rigidly rotating ZAMO surfaces both outside and inside the black hole and the relevance of these objects to a couple of interesting physical problems.
 Publication:

Physical Review D
 Pub Date:
 December 2014
 DOI:
 10.1103/PhysRevD.90.124010
 Bibcode:
 2014PhRvD..90l4010F
 Keywords:

 04.70.s;
 04.70.Bw;
 04.20.Jb;
 Physics of black holes;
 Classical black holes;
 Exact solutions