COMPARISONS OF THE INTERSTELLAR MAGNETIC FIELD DIRECTIONS OBTAINED FROM THE IBEX RIBBON AND INTERSTELLAR POLARIZATIONS
COMPARISONS OF THE INTERSTELLAR MAGNETIC FIELD DIRECTIONS OBTAINED FROM THE IBEX RIBBON AND INTERSTELLAR POLARIZATIONS
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从 IBEX 带获得的星际磁场方向与星际极化的比较
DOI：
10.1088/0004-637x/724/2/1473
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
S. Wiktorowicz
中科院分区：
文献类型：
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作者：
P. Frisch;B. Andersson;A. Berdyugin;H. Funsten;A. M. Magalhães;D. McComas;V. Piirola;N. Schwadron;J. Slavin;S. Wiktorowicz
太阳附近星际磁场（ISMF）空间配置的变化可以通过比较星际边界探测器（IBEX）航天器对高能中性原子（ENA）“带”的观测发现的日光层的 ISMF 方向与从约 40 pc 内恒星的光学偏振数据得出的 ISMF 方向来限制。利用对日光层鼻端~90°范围内~30颗附近恒星的星际偏振观测，我们发现磁极指向黄道坐标λ、β~263°、37°（或银河坐标ℓ、b~38°、23°）时获得了偏振位置角的最佳拟合，不确定度为 ±35° 基于最佳拟合的广泛最小值和数据质量范围。该磁极与 ENA 带状圆弧中心定义的磁极成 33°。当 IBEX ENA 丝带覆盖在日光层上时，可以在垂直于 ISMF 的视线中看到它。局部 ISMF 的偏振和带状方向的相似性表明局部场在数十秒差距的尺度上是相干的。 ISMF矢量方向几乎垂直于通过局部静止标准的局部星际物质（ISM）流，支持与演化的膨胀磁化壳相关的可能的局部ISM起源。发现局部 ISMF 方向相对于宇宙微波背景偶极矩具有奇怪的几何形状。
Variations in the spatial configuration of the interstellar magnetic field (ISMF) near the Sun can be constrained by comparing the ISMF direction at the heliosphere found from the Interstellar Boundary Explorer (IBEX) spacecraft observations of a “Ribbon” of energetic neutral atoms (ENAs), with the ISMF direction derived from optical polarization data for stars within ∼40 pc. Using interstellar polarization observations toward ∼30 nearby stars within ∼90° of the heliosphere nose, we find that the best fits to the polarization position angles are obtained for a magnetic pole directed toward ecliptic coordinates of λ, β ∼ 263°, 37° (or galactic coordinates of ℓ, b ∼ 38°, 23°), with uncertainties of ±35° based on the broad minimum of the best fits and the range of data quality. This magnetic pole is 33° from the magnetic pole that is defined by the center of the arc of the ENA Ribbon. The IBEX ENA ribbon is seen in sight lines that are perpendicular to the ISMF as it drapes over the heliosphere. The similarity of the polarization and Ribbon directions for the local ISMF suggests that the local field is coherent over scale sizes of tens of parsecs. The ISMF vector direction is nearly perpendicular to the flow of local interstellar material (ISM) through the local standard of rest, supporting a possible local ISM origin related to an evolved expanding magnetized shell. The local ISMF direction is found to have a curious geometry with respect to the cosmic microwave background dipole moment.