局部磁泡壁的磁场强度和晶粒取向变化
Magnetic Field Strengths and Grain Alignment Variations in the Local Bubble Wall
摘要：
已知来自星际介质的光学和红外连续偏振通常是由于与磁场对齐的不规则尘埃颗粒。这提供了一个重要的工具来探测这些场的几何形状和强度，特别是如果可以理解晶粒排列效率的变化。在这里，我们研究偏振变化观察到整个本地泡壁，使用一个大的偏振调查北银河帽（\textit{b} $>30^\circ$）从\citet{berdyugin2014}。将这些数据与存档的光度和光谱数据以及\citet{lallement2003}绘制的局部气泡图一起进行分析。我们可以通过假设排列驱动机制是由于来自周围恒星场的辐射来模拟观测数据。特别是，我们发现，分数偏振占主导地位的光从OB协会在150 pc的太阳，但在很大程度上是不敏感的辐射场从红场星。这种行为与辐射晶粒排列理论的预期波长依赖性是一致的。我们还用Davis-Prasekhar-Fermi方法研究了局域磁泡壁中磁场的相对强度。我们发现一个系统地变化的磁场强度分布的证据，在该领域的变化与晶粒排列效率的变化相关，表明相对较高的场强区域可能代表了压缩的壁的流出的相互作用在本地气泡和周围的OB协会相反的流量。
英文摘要：
Optical and infrared continuum polarization from the interstellar medium is known to generally be due to irregular dust grains aligned with the magnetic field. This provides an important tool to probe the geometry and strength of those fields, particularly if the variations in the grain alignment efficiencies can be understood. Here, we examine polarization variations observed throughout the wall of the Local Bubble, using a large polarization survey of the North Galactic cap (\textit{b}$>30^\circ$) from \citet{berdyugin2014}. These data are analyzed together with archival photometric and spectroscopic data along with the mapping of the Local Bubble by \citet{lallement2003}. We can model the observational data by assuming that the alignment driving mechanism is due to the radiation from the surrounding star field. In particular we find that the fractional polarization is dominated by the light from the OB associations within 150 pc of the sun, but is largely insensitive to the radiation field from red field stars. This behavior is consistent with the expected wavelength dependence of radiative grain alignment theory. We also probe the relative strength of the magnetic field in the wall of the Local Bubble using the Davis-Chandrasekhar-Fermi method. We find evidence for a systematically varying field strength distribution, where the variations in the field are correlated with the variations in grain alignment efficiency, indicating that the relatively higher field strength regions might represent a compression of the wall by the interaction of the outflow in the Local Bubble and the opposing flows by the surrounding OB associations.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
