Publikace ÚTF

We investigate a complete family of spacetimes which represent black holes with (Kerr) rotation, Newman-Unti-Tamburino (NUT) twist, acceleration, as well as electric and magnetic charges. These are exact solutions of the Einstein-Maxwell equations with any cosmological constant, such that the (non-null) electromagnetic field is aligned with both the double-degenerate principal null directions (PNDs) of the Weyl tensor. In particular, we explicitly relate various coordinates and the corresponding physical parameters of such solutions, namely the original Pleba & nacute;ski-Demia & nacute;ski (PD) form; the convenient Astorino (A) form, which was found recently and formally improved here (A & thorn;); the Griffiths-Podolsk & yacute; form; and the Podolsk & yacute;-Vr & aacute;tn & yacute; form of the metric. It is demonstrated that, if properly mapped and physically interpreted, all these representations cover the complete class of type D black holes. Using the new A-parameters, the two main PD quartic metric functions are factorized into the product of quadratic expressions, enabling thus an explicit analysis. Moreover, we clarify the role of the twist parameter omega, related to both the Kerr-like rotation and the NUT parameters a and l, respectively. Special attention is paid to the elusive subclass of accelerating NUT black holes with a 1 / 4 0 .