JVLA S- and X-band polarimetry of the merging cluster Abell 2256
JVLA S- and X-band polarimetry of the merging cluster Abell 2256
复制标题
JVLA 合并星团 Abell 2256 的 S 和 X 波段偏振测量
DOI：
10.1093/pasj/psv082
复制
发表时间：
2015
影响因子：
2.3
通讯作者：
Yoshiaki Sofue
中科院分区：
文献类型：
--
作者：
Takeaki Ozawa;Hiroyuki Nakanishi;Takuya Akahori;Kenta Anraku;Motokazu Takizawa;Ikumi Takahashi;Sachiko Onodera;Yuya Tsuda;Yoshiaki Sofue
We report on polarimetry results of a merging cluster of galaxies, Abell 2256, with the Karl G. Jansky Very Large Array (JVLA). We performed new observations with JVLA at the S band (2051–3947 MHz) and X band (8051–9947 MHz) in the C array configuration, and detected significant polarized emissions from the radio relic, Source A, and Source B in this cluster. We calculated the total magnetic-field strengths toward the radio relic using revised equipartition formula, which is 1.8–5.0 μG. With dispersions of Faraday rotation measure, the magnetic-field strengths toward Sources A and B are estimated to be 0.63–1.26 μG and 0.11–0.21 μG, respectively. An extremely high degree of linear polarization, as high as ∼ 35%, about a half of the maximum polarization, was detected toward the radio relic, which indicates highly ordered magnetic lines of force over the beam sizes (∼ 52 kpc). The fractional polarization of the radio relic decreases from ∼ 35% to ∼ 20% at around 3 GHz as the frequency decreases, and is nearly constant between 1.37 and 3 GHz. Both analyses with depolarization models and Faraday tomography suggest multiple depolarization components toward the radio relic and imply the existence of turbulent magnetic fields.
