Magnetic fields in the solar vicinity and in the Galactic halo
Magnetic fields in the solar vicinity and in the Galactic halo
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DOI：
10.1093/mnras/stz1060
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发表时间：
2019-07
影响因子：
4.8
通讯作者：
Jin-Long Xu;Jinlin Han
中科院分区：
文献类型：
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作者：
Jin-Long Xu;Jinlin Han
我们利用距离太阳3千秒差距以内的494颗脉冲星的自转测量值来表征太阳附近的局部大尺度规则磁场以及小尺度磁特征。我们发现银盘中的局部磁场沿局部旋臂运动，磁场强度为1.6 μG，在太阳圈内140秒差距处有一个朝向银心方向的反转。在距离太阳约1千秒差距处，发现了第一象限中朝向人马臂的磁场反转。在本星系晕中，环向场的场强大于1.6 μG。局部小尺度磁泡的研究，通过使用附近的磁泡在这些结构和背后。局部气泡可能有0.5-2 μG的视线磁场强度，主要是在大约90°的方向上;口香糖星云的上壳显示出可能通过压缩将磁场放大了2倍;北极支线没有显著的法拉第旋转，也许它的磁场几乎垂直于视线。在第四象限的一个异常区域，在1 kpc尺度上有1.4 μG的场，这意味着一个亚银河系结构，其有序场与大尺度圆盘场方向相反。我们开发了一个模型的基础上旋转措施的银河系晕的磁场的恒星和平均旋转措施的背景射电源。
We characterize local large-scale regular magnetic fields as well as small-scale magnetic features in the solar vicinity by using the rotation measures of 494 pulsars within 3 kpc from the Sun. The local magnetic field in the Galactic disc is found to follow local spiral arms and to have a field strength of 1.6 μG, with a reversal at 140 pc inside the solar circle in the direction of the Galactic Centre. A field reversal in the first quadrant towards the Sagittarius arm is identified at about 1 kpc from the Sun. In the local Galactic halo, the toroidal fields have a field strength of more than 1.6 μG. Local small-scale magnetic bubbles are investigated by using nearby pulsars in and behind these structures. The Local Bubble might have a line-of-sight magnetic field strength of 0.5–2 μG mainly towardsl∼ 90°; the upper shell of the Gum Nebula shows a possible amplification of the magnetic field with a factor of 2 probably by compression; the North Polar Spur does not contribute significant Faraday rotation, and perhaps its magnetic field is nearly perpendicular to the line of sight. An anomalous region in the fourth quadrant is found to have a field of 1.4 μG over a scale of 1 kpc, which implies a sub-Galactic structure with ordered fields opposite in direction to the large-scale disc field. We develop a model for the magnetic field in the Galactic halo based on the rotation measures of pulsars and averaged rotation measures of background radio sources.