We present the conditions when a Killing-Yano tensor becomes a Nambu tensor. We have shown that in the flat space case all Killing-Yano tensors are Nambu tensors. In the case of Taub-NUT metric and Kerr-Newmann metric we found that a Killing-Yano tensor of order two generate a Nambu tensor of order three. after 1st September 1999 at Institute of Space Sciences,Bucharest-Magurele, Romania e-mail...

The behaviour of the singularities of the rotating black holes under an arbitrary boost is considered on the basis of a complex representation of the Kerr theorem. We give a simple algorithm allowing to get explicit expressions for the metric and the position of the singularities for arbitrary direction and magnitude of the boost, including the ultrarelativistic case. The non-smoothness of the ...

28 Anthony J. Hickey 29 University of North Carolina at Chapel Hill, 1310 Kerr Hall, CB #7360, Chapel Hill, NC 3

The general relativistic magnetohydrodynamic (GRMHD) code of De Villiers & Hawley (2003; DH) has been used to study the accretion of matter onto black holes. It is a highly stable 3 + 1D code that has been used to simulate in great detail the evolution of accretion disks in the spacetime of Kerr black holes. This code has established the ubiquity of energetic axial jets in such environments (De...

A theorem providing a characterisation of Schwarzschildean initial data sets on slices with an asymptotically Euclidean end is proved. This characterisation is based on the proportionality of the Weyl tensor and its D’Alambertian that holds for some vacuum Petrov Type D spacetimes (e.g. the Schwarzschild spacetime, the C-metric, but not the Kerr solution). The 3+1 decomposition of this proporti...

Kerr effect accounts for the change in refractive index of a material with the light intensity and appears in all known optical materials. In this work we analyze Kerr effect in structured superluminal media (e.g some specific types of resonators). We show that Kerr effect in these structures can be cancelled or even reversed (in comparison with the Kerr effect of the material composing the str...

We consider the AdS5 solution deformed by a non-constant dilaton interpolating between the standard AdS (UV region) and flat boundary background (IR region). We show that this dilatonic solution can be generalized to the case of a non-flat boundaries provided that the metric of the boundaries satisfies the vacuum Einstein field equations. As an example, we describe the case when the four-dimens...