Mapping Galactic Magnetic Fields with SPARO

该项目将在今后三个冬季继续在南极运行南极远程观测亚毫米偏振计。 SPARO仪器在Viper 2米望远镜上运行，在第一年的观测之后最近进行了升级。在南极高原异常稳定的冬季天空中，SPARO提供了一个强大的星际磁场探测器。 在亚毫米波长下的测量提供了一种方法，通过测量来自磁性排列的星际尘埃颗粒的热发射的线性偏振，来绘制银河系致密星际区域的磁场。星际磁场通常很难观测，但它们有助于我们理解星际气体（因此可能也是磁场）在其中扮演重要角色的两个一般性问题：银河系中心的研究和星星的形成。 银河系中心是一个辐射非常活跃的区域。 在一些中心，被称为“活动星系核”（AGN），核心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我们太阳系的大小还小，目前的理论认为活动星系核的中心有一个超大质量黑洞。 这里提出的观测目的是（a）证实SPARO最近发现的银河系中心的大规模环形磁场，（B）测试“银河系中心叶”的磁流出模型--一种可能追踪从银河系核心喷出的气体的射电结构，以及（c）绘制形成星星的云的样本中的大尺度磁场，以便研究这些云的细长形状与它们的磁场之间的关系。

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.