FARADAY ROTATION MEASURE DUE TO THE INTERGALACTIC MAGNETIC FIELD
FARADAY ROTATION MEASURE DUE TO THE INTERGALACTIC MAGNETIC FIELD
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DOI：
10.1088/0004-637x/723/1/476
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发表时间：
2010-09
期刊：
影响因子：
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通讯作者：
T. Akahori;D. Ryu
中科院分区：
文献类型：
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作者：
T. Akahori;D. Ryu
研究星系间磁场（IGMF）的性质和起源是宇宙学中的一个突出问题。测量法拉第旋转将是探索宇宙大尺度结构（LSS）中IGMF的一种很有前途的方法。我们利用宇宙结构形成的模拟研究了星系细丝中IGMF引起的法拉第旋转测量（RM）。我们在宇宙LSS中采用了一种基于湍流发电机的模型IGMF，它的平均强度< B > ~ 10 nG，在细丝中的相干长度为几× 100 h−1 kpc。当相干长度小于路径长度时，RM的诱导将是一个随机游走过程，并且我们发现沿视线方向的密度峰对最终RM的贡献占主导地位。目前宇宙中通过细丝的RM的均方根被预测为~ 1 rad m-2。此外，我们预测了|RM|通过细丝的概率分布函数遵循对数正态分布，并且RM在局部宇宙中的功率谱在~ 1 h−1 Mpc的尺度上达到峰值。我们对RM的预测可以用未来的仪器来检验。
Studying the nature and origin of the intergalactic magnetic field (IGMF) is an outstanding problem of cosmology. Measuring Faraday rotation would be a promising method to explore the IGMF in the large-scale structure (LSS) of the universe. We investigated the Faraday rotation measure (RM) due to the IGMF in filaments of galaxies using simulations for cosmological structure formation. We employed a model IGMF based on turbulence dynamo in the LSS of the universe, it has an average strength of 〈B〉 ∼ 10 nG and a coherence length of several × 100 h−1 kpc in filaments. With the coherence length smaller than the path length, the inducement of RM would be a random walk process, and we found that the density peak along the line of sight dominantly contributes to the resultant RM. The root mean square of RM through filaments at the present universe was predicted to be ∼1 rad m-2. In addition, we predicted that the probability distribution function of |RM| through filaments follows the lognormal distribution, and the power spectrum of RM in the local universe peaks at a scale of ∼1 h−1 Mpc. Our prediction of RM could be tested with future instruments.