Relativistic Rotational Darkening of Lightlike Radiation and Von Zeipel's Theorem for Radially Emitting Spheroids
Source: Astrophysics and Space Science, Volume 266, Number 3, 1999 , pp. 371-378(8)
Abstract:It is shown that an outgoing null radiation field in the outer space of a Kerr-Newman black hole is darkened by the rotation of the black hole. This rotational darkening is calculated for a spheroid emitting null radiation normally to its surface, yielding the von Zeipel-like effect that the equatorial region is darkened more strongly than the polar regions. This effect is not confined to the case of black holes but is also observable for relativistically rotating fluid spheroids such as atmospheres of pulsars or neutron stars. Moreover, application to Hawking radiation suggests that the black hole cannot be viewed as a classical black body but that the Hawking radiation is a global geometric effect.
Document Type: Regular Paper
Affiliations: 1: Institut für Mathematik der Ruhr-Universität, D-44780 Bochum, Germany; E-mail: firstname.lastname@example.org 2: Astronomisches Institut der Ruhr-Universität, D-44780 Bochum, Germany (Georg-Büchner-Straße 37, D-97276 Margetshöchheim, Germany)
Publication date: January 1, 1999