تقرير
The scale and redshift variation of density and velocity distributions in dark matter flow and two-thirds law for pairwise velocity
| العنوان: | The scale and redshift variation of density and velocity distributions in dark matter flow and two-thirds law for pairwise velocity |
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| المؤلفون: | Xu, Zhijie (Jay) |
| سنة النشر: | 2022 |
| المجموعة: | Zenodo |
| مصطلحات موضوعية: | cosmology, dark matter, turbulence, probability distribution, simulation, astronomy, astrophysics, dark matter halo, correlation, statistical analysis, self-gravitating, collisionless, N body, density distribution, velocity distribution, two-thirds law, pairwise velocity, dark matter flow |
| الوصف: | The scale and redshift variation of density and velocity distributions in dark matter flow and two-thirds law for pairwise velocity A halo-based non-projection approach is proposed to study the scale and redshift dependence of density and velocity distributions (PDF) in dark matter flow. All particles are divided into halo and out-of-halo particles such that PDF can be studied separately. Without projecting particle fields onto grid, scale dependence is analyzed by counting all pairs on different scales $r$. Redshift dependence is studied via generalized kurtosis. From this analysis, we can demonstrate: i) Delaunay tessellation can be used to reconstruct density field. Density correlations/spectrum are obtained, modeled and compared with theory; ii) $m$th moment of pairwise velocity can be analytically modelled. On small scale, even order moments can be modelled by a two-thirds law \(\langle(\Delta u_L)^{2n}\rangle\propto{(-\epsilon_ur)}^{2/3}\), while odd order moments \(\langle(\Delta u_L)^{2n+1}\rangle=(2n+1)\langle(\Delta u_L)^{2n}\rangle\langle\Delta u_L\rangle\propto{r}\) and satisfy a generalized stable clustering hypothesis (GSCH); iii) Scale dependence is studied for longitudinal velocity \(u_L\) or \(u_L^{'}\), pairwise velocity (velocity difference) \(\Delta u_L=u_L^{'}-u_L\) and velocity sum \(\Sigma u_L=u^{'}_L+u_L\). Fully developed velocity fields are never Gaussian on any scale; iv) On small scale, both \(u_L\) and \(\Sigma u_L\) can be modelled by a \(X\) distribution to maximize system entropy. Distributions of \(\Delta u_L\) is different with its moments analytically derived; v) On large scale, both \(\Delta u_L\) and \(\Sigma u_L\) can be modelled by a logistic function; vi) Redshift evolution of velocity distributions follows prediction of X distribution with a decreasing shape parameter \(\alpha(z)\) to continuously maximize system entropy. Applications of cascade and statistical theory for dark matter and bulge-SMBH evolution: Dark matter particle mass ,size, and properties from energy ... |
| نوع الوثيقة: | report |
| اللغة: | English |
| العلاقة: | handle:110.48550/arXiv.2110.03126; https://zenodo.org/record/6640676Test; https://doi.org/10.48550/arXiv.2202.06515Test; oai:zenodo.org:6640676 |
| DOI: | 10.48550/arXiv.2202.06515 |
| الإتاحة: | https://doi.org/10.48550/arXiv.2202.06515Test https://doi.org/10.5281/zenodo.6569898Test https://doi.org/10.5281/zenodo.6541230Test https://doi.org/10.5281/zenodo.6586212Test https://doi.org/10.5281/zenodo.6569901Test https://doi.org/10.48550/arXiv.2109.12244Test https://doi.org/10.48550/arXiv.2110.05784Test https://doi.org/10.48550/arXiv.2110.09676Test https://doi.org/10.48550/arXiv.2110.13885Test https://doi.org/10.48550/arXiv.2201.12665Test |
| حقوق: | info:eu-repo/semantics/openAccess ; https://creativecommons.org/licenses/by/4.0/legalcodeTest |
| رقم الانضمام: | edsbas.92123FB2 |
| قاعدة البيانات: | BASE |
| DOI: | 10.48550/arXiv.2202.06515 |
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