论文标题
通过晶粒对准和自散射的混合物对Alma HL Tau极化的建模
Modeling of the ALMA HL Tau Polarization by Mixture of Grain Alignment and Self-scattering
论文作者
论文摘要
对于许多原始磁盘，已经观察到（子）毫米波长处的灰尘极化。从理论上讲，多个起源可能有助于极化发射，但仍不确定哪种机制在磁盘毫米极化中占主导地位。为了定量地解决原点，我们对比对和自散射感应极化的混合物进行辐射转移计算，以重现HL Tau磁盘的3.1 mM极化，该磁盘在极化向量中显示了方位角模式。我们发现，晶粒比对和自散射的混合物对于重现HL TAU 3.1 mm极化特性至关重要。我们的模型表明，在3.1 mm处HL TAU的极化可以分解为平行于次要轴平行的自散射的组合，并且平行于与主要轴平行的对齐诱导的极化，每个组件的订单为$ \ sim 0.5 \％$分数。在先前的研究中，这稍微降低了对$ \ sim 70〜 {\ rm〜μm} $的紧密限制，为$ \ sim 130 {\ rm〜μm} $，但需要进一步建模。此外，谷物对齐模型需要有效地构成晶粒，但是在原行星磁盘中复制它的物理学仍然是一个谜。
Dust polarization at (sub)millimeter wavelengths has been observed for many protoplanetary disks. Theoretically, multiple origins potentially contribute to the polarized emission but it is still uncertain what mechanism is dominant in disk millimeter polarization. To quantitatively address the origin, we perform radiative transfer calculations of the mixture of alignment and self-scattering induced polarization to reproduce the 3.1 mm polarization of the HL Tau disk, which shows azimuthal pattern in polarization vectors. We find that a mixture of the grain alignment and self-scattering is essential to reproduce the HL Tau 3.1 mm polarization properties. Our model shows that the polarization of the HL Tau at 3.1 mm can be decomposed to be the combination of the self-scattering parallel to the minor axis and the alignment-induced polarization parallel to the major axis, with the orders of $\sim 0.5\%$ fraction for each component. This slightly eases the tight constraints on the grain size of $\sim 70~{\rm~μm}$ to be $\sim 130 {\rm~μm}$ in the previous studies but further modeling is needed. In addition, the grain alignment model requires effectively prolate grains but the physics to reproduce it in protoplanetary disks is still a mystery.
