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arXiv 0807.2647astro-ph
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宇宙学MHD模拟星族III恒星形成中的Biermann组合

The Biermann Battery in Cosmological MHD Simulations of Population III Star Formation

Hao Xu, Brian W. O'Shea, David C. Collins, Michael L. Norman, Hui Li, Shengtai Li

摘要:

我们报告的第一个自洽的三维自适应网格细化磁流体动力学模拟的人口III恒星形成,包括比尔曼电池效应的结果。我们发现,人口III恒星形成包括这种效果是定性和定量相似的流体动力学(非MHD)宇宙学模拟。我们在恒星形成晕的中心观测到了峰值磁场,峰值为10^-9 G,z约为17.55。由比尔曼电池效应产生的磁场主要是在原始晕演化的早期以低密度和大空间尺度形成的,然后通过压缩和剪切流而增长。在这个计算中看到的场从来没有大到足以成为动力学上重要的场(在任何时候都是β>= 10^{15}),应该被认为是星族III恒星形成过程中存在的最小可能场,并且可能是恒星发电机或磁旋转不稳定性在更高密度和更小空间尺度下的种子场。

英文摘要:

We report the results of the first self-consistent three-dimensional adaptive mesh refinement magnetohydrodynamical simulations of Population III star formation including the Biermann Battery effect. We find that the Population III stars formed including this effect are both qualitatively and quantitatively similar to those from hydrodynamics-only (non-MHD) cosmological simulations. We observe peak magnetic fields of ~10^-9 G in the center of our star-forming halo at z ~ 17.55. The magnetic fields created by the Biermann Battery effect are predominantly formed early in the evolution of the primordial halo at low density and large spatial scales, and then grow through compression and by shear flows. The fields seen in this calculation are never large enough to be dynamically important (with beta >= 10^{15} at all times), and should be considered the minimum possible fields in existence during Population III star formation, and may be seed fields for the stellar dynamo or the magnetorotational instability at higher densities and smaller spatial scales.

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