On the existence of conformal Killing horizons in LRS spacetimes
| Autor: | Sherif, Abbas M. |
|---|---|
| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | Gen Relativ Gravit 56, 15 (2024) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1007/s10714-024-03197-w |
| Popis: | Let $M$ be a locally rotationally symmetric spacetime, and $\xi^a$ a conformal Killing vector for the metric on $M$, lying in the subspace spanned by the unit timelike direction and the preferred spatial direction, and with non-constant components. Under the assumption that the divergence of $\xi^a$ has no critical point in $M$, we obtain the necessary and sufficient condition for $\xi^a$ to generate a conformal Killing horizon. It is shown that $\xi^a$ generates a conformal Killing horizon if and only if either of the components (which coincide on the horizon) is constant along its orbits. That is, a conformal Killing horizon can be realized as the set of critical points of the variation of the component(s) of the conformal Killing vector along its orbits. Using this result, a simple mechanism is provided by which to determine if an arbitrary vector in an expanding LRS spacetime is a conformal Killing vector that generates a conformal Killing horizon. In specializing the case for which $\xi^a$ is a special conformal Killing vector, provided that the gradient of the divergence of $\xi^a$ is non-null, it is shown that LRS spacetimes cannot admit a special conformal Killing vector field, thereby ruling out conformal Killing horizons generated by such vector fields. Comment: 16 pages, no figure, minor typos corrected, accepted for publication in Gen. Relativ. Gravit |
| Databáze: | arXiv |
| Externí odkaz: |
|