Trapping of null geodesics in slowly rotating spacetimes
Abstract Extremely compact objects containing a region of trapped null geodesics could be of astrophysical relevance due to trapping of neutrinos with consequent impact on cooling processes or trapping of gravitational waves. These objects have previously been studied under the assumption of spheric...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2020-11-01
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| Series: | European Physical Journal C: Particles and Fields |
| Online Access: | http://link.springer.com/article/10.1140/epjc/s10052-020-08642-z |
| _version_ | 1818229822604705792 |
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| author | Jaroslav Vrba Martin Urbanec Zdeněk Stuchlík John C. Miller |
| author_facet | Jaroslav Vrba Martin Urbanec Zdeněk Stuchlík John C. Miller |
| author_sort | Jaroslav Vrba |
| collection | DOAJ |
| description | Abstract Extremely compact objects containing a region of trapped null geodesics could be of astrophysical relevance due to trapping of neutrinos with consequent impact on cooling processes or trapping of gravitational waves. These objects have previously been studied under the assumption of spherical symmetry. In the present paper, we consider a simple generalization by studying trapping of null geodesics in the framework of the Hartle–Thorne slow-rotation approximation taken to first order in the angular velocity, and considering a uniform-density object with uniform emissivity for the null geodesics. We calculate effective potentials and escape cones for the null geodesics and how they depend on the parameters of the spacetimes, and also calculate the “local” and “global” coefficients of efficiency for the trapping. We demonstrate that due to the rotation the trapping efficiency is different for co-rotating and retrograde null geodesics, and that trapping can occur even for $$R>3GM/c^2$$ R > 3 G M / c 2 , contrary to what happens in the absence of rotation. |
| first_indexed | 2024-12-12T10:24:43Z |
| format | Article |
| id | doaj.art-f243dd43185d4e77846c3bc5c8f268fa |
| institution | Directory Open Access Journal |
| issn | 1434-6044 1434-6052 |
| language | English |
| last_indexed | 2024-12-12T10:24:43Z |
| publishDate | 2020-11-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | European Physical Journal C: Particles and Fields |
| spelling | doaj.art-f243dd43185d4e77846c3bc5c8f268fa2022-12-22T00:27:28ZengSpringerOpenEuropean Physical Journal C: Particles and Fields1434-60441434-60522020-11-01801112010.1140/epjc/s10052-020-08642-zTrapping of null geodesics in slowly rotating spacetimesJaroslav Vrba0Martin Urbanec1Zdeněk Stuchlík2John C. Miller3Research Centre for Theoretical Physics and Astrophysics, Institute of Physics in Opava, Silesian University in OpavaResearch Centre for Computational Physics and Data Processing, Institute of Physics in Opava, Silesian University in OpavaResearch Centre for Theoretical Physics and Astrophysics, Institute of Physics in Opava, Silesian University in OpavaDepartment of Physics (Astrophysics), University of OxfordAbstract Extremely compact objects containing a region of trapped null geodesics could be of astrophysical relevance due to trapping of neutrinos with consequent impact on cooling processes or trapping of gravitational waves. These objects have previously been studied under the assumption of spherical symmetry. In the present paper, we consider a simple generalization by studying trapping of null geodesics in the framework of the Hartle–Thorne slow-rotation approximation taken to first order in the angular velocity, and considering a uniform-density object with uniform emissivity for the null geodesics. We calculate effective potentials and escape cones for the null geodesics and how they depend on the parameters of the spacetimes, and also calculate the “local” and “global” coefficients of efficiency for the trapping. We demonstrate that due to the rotation the trapping efficiency is different for co-rotating and retrograde null geodesics, and that trapping can occur even for $$R>3GM/c^2$$ R > 3 G M / c 2 , contrary to what happens in the absence of rotation.http://link.springer.com/article/10.1140/epjc/s10052-020-08642-z |
| spellingShingle | Jaroslav Vrba Martin Urbanec Zdeněk Stuchlík John C. Miller Trapping of null geodesics in slowly rotating spacetimes European Physical Journal C: Particles and Fields |
| title | Trapping of null geodesics in slowly rotating spacetimes |
| title_full | Trapping of null geodesics in slowly rotating spacetimes |
| title_fullStr | Trapping of null geodesics in slowly rotating spacetimes |
| title_full_unstemmed | Trapping of null geodesics in slowly rotating spacetimes |
| title_short | Trapping of null geodesics in slowly rotating spacetimes |
| title_sort | trapping of null geodesics in slowly rotating spacetimes |
| url | http://link.springer.com/article/10.1140/epjc/s10052-020-08642-z |
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