Quasi-local measurements and orientation in black-hole fields

Article

Quasi-local measurements and orientation in black-hole fields

Semerák, O.; de Felice, F.

Class. Quantum Grav. 14(8), 2381-2392 (1997)

Abstract

An observer travelling in the Kerr - Newman field can deduce the parameters of the host spacetime and those of his orbit from quasi-local measurements only. A way to achieve this result is first to set oneself into the orbit of an equatorial canonical (Carter) observer, and then measure (i) the electric and magnetic fields, (ii) the linear velocities of the equatorial circular geodesics at a given radius (and possibly also those of geodesics which are purely latitudinal locally), (iii) one's thrust, (iv) the angular frequency of the `Pharaoh's fan' and (v) the angular velocity of precession of comoving gyroscopes. We show that the local experiments which are necessary to acquire all the desired information can be performed in a general Kerr - Newman background and also in the special cases of Kerr, Reissner - Nordström and Schwarzschild spacetimes. We point out a close connection between the behaviour of one of the observer's devices - the `Pharaoh's fan' - and the Wilkins effect.

Institute authors

Semerák, Oldřich

Supported by

GACR 202/96/0206 — Relativistic physics and astrophysics
GAUK 230/1996 — Relativistická teorie gravitace, astrofyzika a kosmologie

BibTeX

@article{UTF750,
  author        = {Semerák, O. and de Felice, F.},
  title         = {{Quasi-local measurements and orientation in black-hole fields}},
  journal       = {Class. Quantum Grav.},
  volume        = {14},
  number        = {8},
  pages         = {2381-2392},
  year          = {1997},
  month         = {8},
  doi           = {10.1088/0264-9381/14/8/030},
}