ORIGIN OF MAGNETIC FIELD IN THE INTRACLUSTER MEDIUM: PRIMORDIAL OR ASTROPHYSICAL?
ORIGIN OF MAGNETIC FIELD IN THE INTRACLUSTER MEDIUM: PRIMORDIAL OR ASTROPHYSICAL?
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DOI：
10.1088/0004-637x/797/2/133
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发表时间：
2014-12-20
影响因子：
4.9
通讯作者：
Cho, Jungyeon
中科院分区：
文献类型：
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作者：
Cho, Jungyeon
星系团中磁场的起源仍然是一个未解决的问题，这在很大程度上是由于我们对初始种子磁场的理解不足。如果种子磁场具有原始起源，那么在大规模结构形成之前就存在大规模的普遍磁场。另一方面，如果它们是从天体物理体中喷射出来的，那么它们在注入时高度局限于空间中。在本文中，使用湍流发电机模型的高磁普朗特数流体，我们发现的种子磁场的约束。基于团内介质（ICM）中Spitzer粘度的流体动力学雷诺数被认为小于O（10（2）），而磁雷诺数可以大得多。在这种情况下，如果种子磁场具有原始起源，它们应该比O（10（-11））G更强，这非常接近宇宙微波背景观测设定的O（10（-9））G上限。另一方面，如果种子磁场是从天体中喷射出来的，任何强于O（10（-9））G的种子磁场都可以安全地磁化ICM。因此，原始磁场不太可能是ICM现今磁场的直接来源。
The origin of magnetic fields in galaxy clusters is still an unsolved problem that is largely due to our poor understanding of initial seed magnetic fields. If the seed magnetic fields have primordial origins, it is likely that large-scale pervasive magnetic fields were present before the formation of the large-scale structure. On the other hand, if they were ejected from astrophysical bodies, then they were highly localized in space at the time of injection. In this paper, using turbulence dynamo models for high magnetic Prandtl number fluids, we find constraints on the seed magnetic fields. The hydrodynamic Reynolds number based on the Spitzer viscosity in the intracluster medium (ICM) is believed to be less than O(10(2)), while the magnetic Reynolds number can be much larger. In this case, if the seed magnetic fields have primordial origins, they should be stronger than O(10(-11))G, which is very close to the upper limit of O(10(-9))G set by the cosmic microwave background observations. On the other hand, if the seed magnetic fields were ejected from astrophysical bodies, any seed magnetic fields stronger than O(10(-9))G can safely magnetize the ICM. Therefore, it is less likely that primordial magnetic fields are the direct origin of present-day magnetic fields in the ICM.