Mapping Galactic Magnetic Fields with SPARO

使用 SPARO 绘制银河磁场图

• 批准号: 0130389
• 负责人: Giles Novak
• 金额: $ 30万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-01 至 2006-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0130389&HistoricalAwards=false
• 关键词: Mapping; Galactic; Magnetic; Fields; SPARO

This project will continue the operation of the Submillimeter Polarimeter for Antarctic Remote Observations (SPARO) at the South Pole for the next three winter seasons. The SPARO instrument is operated on the Viper 2-meter telescope, and has recently been upgraded following its first year of observations. In the exceptionally transmissive and stable winter-time skies over the Antarctic plateau, SPARO provides a powerful probe of magnetic fields in interstellar regions. Measurements at submillimeter wavelengths provide a method for mapping magnetic fields in the denser interstellar regions of the galaxy by measuring the linear polarization of thermal emission from magnetically aligned interstellar dust grains. Interstellar magnetic fields are generally difficult to observe, but they can contribute to our understanding of two general problems in which interstellar gas (and thus probably also magnetic fields) play important roles: the study of the galactic center, and star formation. The galactic center is a highly radiationally active region. In some centers, known as "active galactic nuclei" (AGN), the nucleus or central core produces more radiation than the entire rest of the galaxy. The size of an AGN can be smaller than the size of our solar system, and current theory suggests that there is a supermassive black hole at the center of an AGN. Observations proposed here are aimed at (a) confirming SPARO's recent discovery of a large-scale toroidal magnetic field at the galactic center, (b) testing a magnetic outflow model for the "Galactic Center Lobe" - a radio structure possibly tracing gas that has been ejected from the galactic nucleus, and (c) mapping large-scale magnetic fields in a sample of star forming clouds in order to study the relationship between the elongated shapes of these clouds and their magnetic fields.

该项目将在接下来的三个冬季继续在南极运行亚毫米旋光仪（SPARO）。 SPARO 仪器在 Viper 2 米望远镜上运行，在第一年的观测后最近进行了升级。在南极高原上空异常透明且稳定的冬季天空中，SPARO 为星际区域的磁场提供了强大的探测器。 亚毫米波长的测量提供了一种通过测量磁性排列的星际尘埃颗粒热发射的线性偏振来绘制星系较密集星际区域磁场的方法。星际磁场通常很难观察到，但它们可以帮助我们理解星际气体（因此也可能是磁场）发挥重要作用的两个一般问题：银河系中心的研究和恒星的形成。 银河系中心是一个辐射高度活跃的区域。 在一些被称为“活动星系核”（AGN）的中心，核或中央核心产生的辐射比整个星系的其余部分更多。 活动星系核的大小可能比太阳系还要小，目前的理论表明活动星系核的中心存在一个超大质量黑洞。 这里提出的观测旨在（a）证实 SPARO 最近在银河系中心发现的大规模环形磁场，（b）测试“银河系中心瓣”的磁流出模型 - 一种可能追踪从银河核喷射出的气体的射电结构，以及（c）绘制恒星形成云样本中的大规模磁场，以研究恒星形成云中的大规模磁场之间的关系 这些云的细长形状及其磁场。