| 1. |
- Bengtsson, Ingemar, et al.
(författare)
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Classics illustrated: limits of spacetimes
- 2014
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Ingår i: Classical and quantum gravity. - : IOP Publishing. - 0264-9381 .- 1361-6382. ; 31:20
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Tidskriftsartikel (refereegranskat)abstract
- We carefully study the e→m and e→0 limits of the Reissner-Nordström spacetime using Geroch's definition of limits of spacetimes. This is implemented by embedding the one-parameter family of spacetimes in anti-de Sitter space, and as a result we obtain metrically correct Penrose diagrams. For e→m two distinct limits are studied.
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| 2. |
- Bengtsson, Ingemar, et al.
(författare)
-
What are extremal Kerr Killing vectors up to?
- 2012
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Ingår i: Classical and quantum gravity. - : IOP Publishing. - 0264-9381 .- 1361-6382. ; 29:21
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Tidskriftsartikel (refereegranskat)abstract
- In the extremal Kerr spacetime the horizon Killing vector field is null on a timelike hypersurface crossing the horizon at a fixed latitude and spacelike on both sides of the horizon in the equatorial plane. We explain in some detail how this behavior is consistent with the existence of timelike Killing vectors everywhere off the horizon, and how it arises in a limit from the Kerr spacetime where there is a similar hypersurface strictly outside the horizon.
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| 3. |
- Bengtsson, Ingemar, et al.
(författare)
-
Anti-de Sitter Quotients: When Are They Black Holes?
- 2008
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Ingår i: Classical and quantum gravity. - 0264-9381 .- 1361-6382. ; 25, s. 095019-
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Tidskriftsartikel (refereegranskat)abstract
- e point out that the BTZ black holes, and their relatives, can be defined in a cleaner way than they originally were. The covering space can be taken to be anti-de Sitter space, period, while splits up into components due to Misner singularities. Our definition permits us to choose between two conflicting claims concerning BTZ black holes in (3 + 1) dimensions.
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| 4. |
- Bengtsson, Ingemar, et al.
(författare)
-
Black hole lattices under the microscope
- 2018
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Ingår i: Classical and quantum gravity. - : IOP Publishing. - 0264-9381 .- 1361-6382. ; 35:14
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Tidskriftsartikel (refereegranskat)abstract
- It is known how to choose initial data for Einstein's equations describing an arbitrary number of black holes at a moment of time symmetry. This idea has been used to give insight into the cosmological averaging problem. We study the local curvature of the initial data space, for configurations of 8, 120, or 600 black holes obtained by choosing points either regularly or randomly on a 3-sphere. We conclude that the asymptotic regions are remarkably close to that of Schwarzschild, while the region in between shows interesting behaviour. The cosmological back reaction as defined in the recent literature is actually a bit smaller for the random configurations.
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