标题： JCMT POL-2 和 ALMA 在 6000-100 天文单位尺度上对原恒星 B335 的偏振观测：在观测和磁流体动力学模拟中联系磁场和气体运动学 显示英文标题

标题： JCMT POL-2 and ALMA polarimetric observations of 6000-100 au scales in the protostar B335: linking magnetic field and gas kinematics in observations and MHD simulations

摘要： 我们分析了来自6000 au到100 au尺度的Class 0原恒星B335的磁场结构，这些分析基于我们的JCMT POL-2观测和ALMA档案极化数据。 为了解释观测结果，我们进行了一系列（非）理想MHD模拟，模拟旋转非湍流致密核心的坍缩，其初始条件与在B335中观测到的相同，并生成合成极化图。 我们JCMT和模拟结果的比较表明，B335在6000 au尺度上的磁场被压缩，并且沿东西方向与双极喷流很好地对齐。 在所有模拟中，ALMA极化结果最好由初始质量-通量比为9.6的弱磁场模型来解释。 然而，我们发现，在弱磁场情况下，我们模拟中的100 au尺度上的旋转速度和盘大小比观测估计值大几个因子。 我们模拟与用SMA和ALMA观测到的B335气体运动学的独立比较支持初始质量-通量比小于4.8的强磁场模型。 我们讨论了从极化和分子线观测中推断出不同磁场强度的两种可能性，(1) B335中旋转能与引力能的高估和(2)由于在100 au尺度上的散射导致极化强度的额外贡献。 显示英文摘要

摘要： We present our analysis of the magnetic field structures from 6000 au to 100 au scales in the Class 0 protostar B335 inferred from our JCMT POL-2 observations and the ALMA archival polarimetric data. To interpret the observational results, we perform a series of (non-)ideal MHD simulations of the collapse of a rotating non-turbulent dense core, whose initial conditions are adopted to be the same as observed in B335, and generate synthetic polarization maps. The comparison of our JCMT and simulation results suggests that the magnetic field on a 6000 au scale in B335 is pinched and well aligned with the bipolar outflow along the east-west direction. Among all our simulations, the ALMA polarimetric results are best explained with weak magnetic field models having an initial mass-to-flux ratio of 9.6. However, we find that with the weak magnetic field, the rotational velocity on a 100 au scale and the disk size in our simulations are larger than the observational estimates by a factor of several. An independent comparison of our simulations and the gas kinematics in B335 observed with the SMA and ALMA favors strong magnetic field models with an initial mass-to-flux ratio smaller than 4.8. We discuss two possibilities resulting in the different magnetic field strengths inferred from the polarimetric and molecular-line observations, (1) overestimated rotational-to-gravitational energy in B335 and (2) additional contributions in the polarized intensity due to scattering on a 100 au scale.