دورية أكاديمية
Maximum entropy distributions of dark matter in ΛCDM cosmology
| العنوان: | Maximum entropy distributions of dark matter in ΛCDM cosmology |
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| المؤلفون: | Xu, Zhijie (Jay) |
| المصدر: | Astronomy & Astrophysics 675 A92 |
| سنة النشر: | 2023 |
| المجموعة: | Zenodo |
| مصطلحات موضوعية: | cosmology, dark matter, turbulence, simulation, astronomy, astrophysics, dark matter halo, correlation, statistical analysis, self-gravitating, collisionless, N body, maximum entropy, velocity distribution, energy distribution, speed distribution |
| الوصف: | Maximum entropy distributions of dark matter in ΛCDM cosmology Small-scale challenges to ΛCDM cosmology require a deeper understanding of dark matter physics. This paper aims to develop the maximum entropy distributions for dark matter particle velocity (denoted by X), speed (denoted by Z), and energy (denoted by E) that are especially relevant on small scales where system approaches full virialization. For systems involving long-range interactions, a spectrum of halos of different sizes is required to form to maximize system entropy. While the velocity in halos can be Gaussian, the velocity distribution throughout the entire system, involving all halos of different sizes, is non-Gaussian. With the virial theorem for mechanical equilibrium, we applied the maximum entropy principle to the statistical equilibrium of entire system, such that the maximum entropy distribution of velocity (the X distribution) could be analytically derived. The halo mass function was not required in this formulation, but it did indeed result from the maximum entropy. The predicted X distribution involves a shape parameter \(\alpha\) and a velocity scale, \(v_0\). The shape parameter \(\alpha\) reflects the nature of force (\(\alpha\rightarrow0\) for long-range force or \(\alpha\rightarrow\infty\) for short-range force). Therefore, the distribution approaches Laplacian with \(\alpha\rightarrow0\) and Gaussian with \(\alpha\rightarrow\infty\). For an intermediate value of \(\alpha\), the distribution naturally exhibits a Gaussian core for \(v\ll v_0\) and exponential wings for \(v\gg v_0\), as confirmed by N-body simulations. From this distribution, the mean particle energy of all dark matter particles with a given speed, v, follows a parabolic scaling for low speeds (\(\propto v^2\) for \(v\ll v_0\) in halo core region, i.e., "Newtonian") and a linear scaling for high speeds (\(\propto v\) for \(v\gg v_0\) in halo outskirt, i.e., exhibiting "non-Newtonian" behavior in MOND due to long-range gravity). We compared our results against ... |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| العلاقة: | https://zenodo.org/record/6640373Test; https://doi.org/10.48550/arXiv.2110.03126Test; oai:zenodo.org:6640373 |
| DOI: | 10.48550/arXiv.2110.03126 |
| الإتاحة: | https://doi.org/10.48550/arXiv.2110.03126Test https://doi.org/10.5281/zenodo.6569901Test https://doi.org/10.5281/zenodo.6569898Test https://doi.org/10.5281/zenodo.6541230Test https://doi.org/10.5281/zenodo.6586212Test https://doi.org/10.48550/arXiv.2109.12244Test https://doi.org/10.48550/arXiv.2109.09985Test https://doi.org/10.48550/arXiv.2110.05784Test https://doi.org/10.48550/arXiv.2110.09676Test https://doi.org/10.48550/arXiv.2110.13885Test |
| حقوق: | info:eu-repo/semantics/openAccess ; https://creativecommons.org/licenses/by/4.0/legalcodeTest |
| رقم الانضمام: | edsbas.E4B309D6 |
| قاعدة البيانات: | BASE |
| DOI: | 10.48550/arXiv.2110.03126 |
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