论文标题
大型银河磁场中的螺旋性
Helicity in the Large-Scale Galactic Magnetic Field
论文作者
论文摘要
我们从银河系全套无线电极化调查中搜索数据中磁性螺旋性的观察性特征。这样的检测将有助于确认该场的发电机起源，并可能为其形状提供新的观察性约束。我们将观察结果与简单的螺旋场和更复杂的磁场的模拟观察结果进行了比较，该观察结果是从解决方案到发电机方程的更复杂的场。我们的模拟观察结果表明，磁场的大尺度螺旋性反映在源自观察到的同步辐射的分数极化的大尺度结构中，以及弥漫性银河系发射的弥散性半乳酸同步辐射的深度。将模型与观测值进行比较提供了证据证明存在四极磁场的存在，并在银河系的两个半球中都远离观察者。由于没有理由相信与其他星系相比，银河磁场是不寻常的，因此该结果为星系中大规模磁场的发电机起源提供了进一步的支持。
We search for observational signatures of magnetic helicity in data from all-sky radio polarization surveys of the Milky Way Galaxy. Such a detection would help confirm the dynamo origin of the field and may provide new observational constraints for its shape. We compare our observational results to simulated observations for both a simple helical field, and for a more complex field that comes from a solution to the dynamo equation. Our simulated observations show that the large-scale helicity of a magnetic field is reflected in the large-scale structure of the fractional polarization derived from the observed synchrotron radiation and Faraday depth of the diffuse Galactic synchrotron emission. Comparing the models with the observations provides evidence for the presence of a quadrupolar magnetic field with a vertical component that is pointing away from the observer in both hemispheres of the Milky Way Galaxy. Since there is no reason to believe that the Galactic magnetic field is unusual when compared to other galaxies, this result provides further support for the dynamo origin of large-scale magnetic fields in galaxies.
