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| Autori principali: | , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2024
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| Soggetti: | |
| Accesso online: | https://arxiv.org/abs/2411.02550 |
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| _version_ | 1866915523233579008 |
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| author | Hsu, Yi-Hsiung Lasenby, Anthony Barker, Will Durakovic, Amel Hobson, Michael |
| author_facet | Hsu, Yi-Hsiung Lasenby, Anthony Barker, Will Durakovic, Amel Hobson, Michael |
| contents | Spherically symmetric Einstein-æther (EÆ) theory with a Maxwell-like kinetic term is revisited. We consider a general choice of the metric and the æther field, finding that:~(i) there is a gauge freedom allowing one always to use a diagonal metric; and~(ii) the nature of the Maxwell equation forces the æther field to be time-like in the coordinate basis. We derive the vacuum solution and confirm that the innermost stable circular orbit (ISCO) and photon ring are enlarged relative to general relativity (GR). Buchdahl's theorem in EÆ theory is derived. For a uniform physical density, we find that the upper bound on compactness is always lower than in GR. Additionally, we observe that the Newtonian and EÆ radial acceleration relations run parallel in the low pressure limit. Our analysis of EÆ theory may offer novel insights into its interesting phenomenological generalization: Æther--scalar--tensor theory (ÆST). |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2411_02550 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Buchdahl bound, photon ring, ISCO and radial acceleration in Einstein-æther theory Hsu, Yi-Hsiung Lasenby, Anthony Barker, Will Durakovic, Amel Hobson, Michael General Relativity and Quantum Cosmology Astrophysics of Galaxies Spherically symmetric Einstein-æther (EÆ) theory with a Maxwell-like kinetic term is revisited. We consider a general choice of the metric and the æther field, finding that:~(i) there is a gauge freedom allowing one always to use a diagonal metric; and~(ii) the nature of the Maxwell equation forces the æther field to be time-like in the coordinate basis. We derive the vacuum solution and confirm that the innermost stable circular orbit (ISCO) and photon ring are enlarged relative to general relativity (GR). Buchdahl's theorem in EÆ theory is derived. For a uniform physical density, we find that the upper bound on compactness is always lower than in GR. Additionally, we observe that the Newtonian and EÆ radial acceleration relations run parallel in the low pressure limit. Our analysis of EÆ theory may offer novel insights into its interesting phenomenological generalization: Æther--scalar--tensor theory (ÆST). |
| title | Buchdahl bound, photon ring, ISCO and radial acceleration in Einstein-æther theory |
| topic | General Relativity and Quantum Cosmology Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2411.02550 |