| Texto completo | |
| Autor(es): |
Vieira, Ronaldo S. S.
;
Kluzniak, Wlodek
;
Abramowicz, Marek
Número total de Autores: 3
|
| Tipo de documento: | Artigo Científico |
| Fonte: | PHYSICAL REVIEW D; v. 95, n. 4, p. 6-pg., 2017-02-08. |
| Resumo | |
The sum of squared epicyclic frequencies of nearly circular motion (omega(2)(r) + omega(2)(theta).) in axially symmetric configurations of Newtonian gravity is known to depend both on the matter density and on the angular velocity profile of circular orbits. It was recently found that this sum goes to zero at the photon orbits of Schwarzschild and Kerr spacetimes. However, these are the only relativistic configurations for which such a result exists in the literature. Here, we extend the above formalism in order to describe the analogous relation for geodesic motion in arbitrary static, axially symmetric, asymptotically flat solutions of general relativity. The sum of squared epicyclic frequencies is found to vanish at photon radii of vacuum solutions. In the presence of matter, we obtain that omega(2)(r) +omega(2)(theta) > 0 for perturbed timelike circular geodesics on the equatorial plane if the strong energy condition holds for the matter-energy fluid of spacetime; in vacuum, the allowed region for timelike circular geodesic motion is characterized by the inequality above. The results presented here may be of use to shed light on general issues concerning the stability of circular orbits once they approach photon radii, mainly the ones corresponding to stable photon motion. (AU) | |
| Processo FAPESP: | 10/00487-9 - Estudo dinâmico de sistemas autogravitantes newtonianos e pós-newtonianos com matéria escura |
| Beneficiário: | Ronaldo Savioli Sumé Vieira |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado |
| Processo FAPESP: | 13/01001-0 - Um estudo dinâmico da esfera de captura de Eddington |
| Beneficiário: | Ronaldo Savioli Sumé Vieira |
| Modalidade de apoio: | Bolsas no Exterior - Estágio de Pesquisa - Doutorado |
| Processo FAPESP: | 15/10577-9 - Caos e integrabilidade em discos galácticos |
| Beneficiário: | Ronaldo Savioli Sumé Vieira |
| Modalidade de apoio: | Bolsas no Brasil - Pós-Doutorado |