Report
Bianchi IX gravitational collapse of matter inhomogeneities
| العنوان: | Bianchi IX gravitational collapse of matter inhomogeneities |
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| المؤلفون: | Giani, Leonardo, Piattella, Oliver F., Kamenshchik, Alexander Yu. |
| سنة النشر: | 2021 |
| المجموعة: | Astrophysics General Relativity and Quantum Cosmology |
| مصطلحات موضوعية: | General Relativity and Quantum Cosmology, Astrophysics - Cosmology and Nongalactic Astrophysics |
| الوصف: | We investigate a model of gravitational collapse of matter inhomogeneities where the latter are modelled as Bianchi type IX (BIX) spacetimes. We found that this model contains, as limiting cases, both the standard spherical collapse model and the Zeldovich solution for a 1-dimensional perturbation. We study how these models are affected by small anisotropic perturbations within the BIX potential. For the spherical collapse case, we found that the model is equivalent to a closed FLRW Universe filled with matter and two perfect fluids representing the anisotropic contributions. From the linear evolution up to the turnaround, the anisotropies effectively shift the value of the FLRW spatial curvature, because the fluids have effective Equation of State (EoS) parameters $w \approx -1/3$. Then we estimate the impact of such anisotropies on the number density of haloes using the Press-Schechter formalism. If a fluid description of the anisotropies is still valid after virialization, the averaged over time EoS parameters are $w\approx 1/3$. Using this and demanding hydrostatic equilibrium, we find a relation between the mass $M$, the average radius $R$ and the pressure $p$ of the virialized final structure. When we consider perturbations of the Zeldovich solution, our qualitative analysis suggests that the so called \textit{pancakes} exhibit oscillatory behavior, as would be expected in the case of a vacuum BIX spacetime. Comment: v2, replaced to match the accepted version. Comments are welcome! |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1088/1475-7516/2022/03/028 |
| URL الوصول: | http://arxiv.org/abs/2112.01869 |
| رقم الانضمام: | edsarx.2112.01869 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1088/1475-7516/2022/03/028 |
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