New Spacetime Solutions for Spiral Galaxies
Fuente:
arXiv
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| Format: | Preprint |
| Publié: |
2024
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| _version_ | 1866908606358618112 |
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| author | Sengupta, Sandipan |
| author_facet | Sengupta, Sandipan |
| contents | We find a set of spacetime solutions whose rotation curves approach a flat profile at large radii, as observed for spiral galaxies. The associated stress-energy tensor reflects a positive mass and anisotropic pressure. The spatially averaged equation of state, which parametrizes these infinity of solutions, exhibits a lower bound: $w> -\frac{1}{3}$. As examples, we present the spacetime metrics for non-ideal `dust' and `radiation'. The Einstein clusters emerge as another special class, whose EOS parameter is predicted to be given by the limiting rotational velocity as: $w=\frac{v^2}{3c^2}$. Analyzing the gravitational deflection of a light ray penetrating a large halo, we find the correction to the Einsteinian bending angle to be $\Big(\frac{2+3w}{1+3w}\Big)π\frac{v^2}{c^2}$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2404_13118 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | New Spacetime Solutions for Spiral Galaxies Sengupta, Sandipan General Relativity and Quantum Cosmology Astrophysics of Galaxies We find a set of spacetime solutions whose rotation curves approach a flat profile at large radii, as observed for spiral galaxies. The associated stress-energy tensor reflects a positive mass and anisotropic pressure. The spatially averaged equation of state, which parametrizes these infinity of solutions, exhibits a lower bound: $w> -\frac{1}{3}$. As examples, we present the spacetime metrics for non-ideal `dust' and `radiation'. The Einstein clusters emerge as another special class, whose EOS parameter is predicted to be given by the limiting rotational velocity as: $w=\frac{v^2}{3c^2}$. Analyzing the gravitational deflection of a light ray penetrating a large halo, we find the correction to the Einsteinian bending angle to be $\Big(\frac{2+3w}{1+3w}\Big)π\frac{v^2}{c^2}$. |
| title | New Spacetime Solutions for Spiral Galaxies |
| topic | General Relativity and Quantum Cosmology Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2404.13118 |