Ulm 2004 – wissenschaftliches Programm
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GR: Gravitation und Relativitätstheorie
GR 3: Klassische Gravitationstheorie, Schwarze Löcher, Astrophysik
GR 3.3: Fachvortrag
Mittwoch, 17. März 2004, 15:00–15:20, H20
Stationary Black Holes with Static and Counterrotating Horizons — •Jutta Kunz1, Burkhard Kleihaus1, and Francisco Navarro-Lérida2 — 1Institut für Physik, Universität Oldenburg, D-26111 Oldenburg — 2Dept. de Física Atómica, Molecular y Nuclear, Ciencias FísicaUniversidad Complutense de Madrid, E-28040 Madrid, Spains
We present rotating black holes in Einstein-Maxwell-dilaton (EMD) theory, treating the dilaton coupling constant γ as a free parameter. Rotating charged EMD black holes are known exactly only for Einstein-Maxwell theory (γ=0) and for Kaluza-Klein (KK) theory (γ=√3).
Dyonic extremal KK black holes, carrying electric charge Q and magnetic charge P, possess the surprising property, that they can carry finite angular momentum |J|≤ |PQ|, while they possess a vanishing horizon angular velocity Ω and no ergoregion. For these black holes the angular momentum can be increased from zero to |PQ| without changing their mass or their charges.
Here we show that when the dilaton coupling constant exceeds the Kaluza-Klein value, whole families of non-extremal black holes with finite angular momentum |J|≤ |PQ| exist, which possess vanishing horizon angular velocity and no ergoregion. These stationary black holes with static horizon bifurcate from the static black holes. Their mass decreases with increasing angular momentum, their horizons are prolate. Moreover, we demonstrate, that even stranger black holes appear: black holes with counterrotating horizon, i.e. their horizon angular velocity Ω and their total angular momentum J have opposite signs.