Collaborative Research: Observational testing of interstellar grain alignment theory

合作研究：星际颗粒排列理论的观测测试

• 批准号: 1109295
• 负责人: Alexandre Lazarian
• 金额: $ 14.53万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-10-01 至 2016-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1109295&HistoricalAwards=false
• 关键词: Collaborative; Research; Observational; testing; interstellar

The collaborative research lead by Dr. Andersson (Universities Space Research Association), Dr. Jones (University of Minnesota), and Dr. Lazarian (University of Wisconsin, Madison) advances our ability to trace magnetic fields in the interstellar medium and molecular clouds through new multi-wavelength observations and theoretical modeling. It leads to a better understanding of the foregrounds to the cosmic microwave background (CMB) polarization through targeted observations of interstellar grain alignment and modeling based on the leading theoretical paradigm. The combined new quantitative effort addresses interstellar grain alignment mechanisms. A quantitative theory based on radiative alignment torques provides specific, testable predictions of the grain alignment as functions of the environment and grain characteristics. Observations, employing optical and near-infrared (NIR) polarimetry, directly probe the theoretical predictions of the variations of grain alignment efficiencies from the molecular cloud surfaces to the depths where (sub-)mm wave polarized emission is observed. Extensive modeling of the grain alignment, simulating the polarization arising from aligned grains, supports interpretations of the observations. A quantitative understanding of the alignment mechanism is important to understand the structure and strength of the magnetic field (through the geometry of the polarization vectors and the Chandrasekhar-Fermi method, respectively). The impact on related research ranges from models of star formation (through a reliable magnetic field tracing) to the physics of Early Universe (through a reliable separation of polarized dust foreground from the CMB polarized radiation) as well as a better understandinging micro-physics of interstellar dust grains. This project trains young researchers and graduate students in the acquisition, analysis and interpretation of the optical and NIR observations, and on computational models necessary for the study of astrophysical magnetic fields and the nature of interstellar polarization.

由安德森博士（大学空间研究协会）、琼斯博士（明尼苏达大学）和拉扎里安博士（威斯康星大学麦迪逊分校）领导的合作研究提高了我们追踪星际介质和分子云中磁场的能力新的多波长观测和理论建模。通过基于领先理论范式对星际颗粒排列和建模进行有针对性的观测，可以更好地了解宇宙微波背景（CMB）偏振的前景。新的联合定量工作解决了星际颗粒排列机制。基于辐射对准扭矩的定量理论提供了作为环境和颗粒特征函数的颗粒对准的具体的、可测试的预测。采用光学和近红外 (NIR) 偏振测量的观测，直接探索从分子云表面到观察到（亚）毫米波偏振发射的深度的晶粒排列效率变化的理论预测。晶粒排列的广泛建模，模拟排列晶粒产生的偏振，支持对观测结果的解释。对排列机制的定量理解对于理解磁场的结构和强度非常重要（分别通过极化矢量的几何形状和钱德拉塞卡-费米方法）。对相关研究的影响范围从恒星形成模型（通过可靠的磁场追踪）到早期宇宙的物理学（通过可靠地分离偏振尘埃前景与 CMB 偏振辐射），以及更好地理解早期宇宙的微观物理学。星际尘埃颗粒。该项目培训年轻研究人员和研究生获取、分析和解释光学和近红外观测结果，以及研究天体物理磁场和星际极化性质所需的计算模型。