Magnetic fields, outflows and feedback in spiral galaxies

螺旋星系中的磁场、流出和反馈

• 批准号: 184201-2011
• 负责人: Irwin, Judith
• 金额: $ 3.5万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=569704
• 关键词: Magnetic; fields; outflows; feedback; spiral

Spiral galaxies are surrounded by gaseous halos which show considerable structure and connect the interstellar medium (ISM, the gas between the stars) within the galaxy disk to the surrounding environment. The evidence is mounting that these halos are dynamic entities; that is, they manifest the expulsion of dust, gas (ionized, neutral and molecular), cosmic rays, and magnetic fields from galaxy disks. What is not yet clear is how many and what type of galaxy is more likely to display such halos, how much expelled material cycles back to the disk again, and how much material leaves the galaxy, enriching the intergalactic medium (IGM, the low density gas between galaxies). We know that such outflows (or `feedback') play a crucial role in the formation of galaxies, yet the nature and details of this activity are not well known. The evidence suggests that galaxy evolution (including that of our own Milky Way) is strongly influenced by such activity, yet we do not even know the main drivers of such activity. The goals of my proposal are to answer these questions. Moreover, for the first time, the 3-dimensional magnetic field structure in galaxy halos will be mapped, answering long-standing questions about how these fields are formed. To accomplish these goals, I will use the Expanded Very Large Array (EVLA) in New Mexico, a joint Canada-USA-Mexico radio telescope upgrade that results in an order of magnitude improvement in sensitivity over the previous instrument. The EVLA proposal, which I am leading, has been awarded an exceptional 405 hours of observing time to address the above goals. With an international team of collaborators, we will produce definitive answers to halo research questions and produce a data set of true legacy value for years to come. In the process, the opportunities for the training of highly qualified personnel are exceptional (10 for me alone), not only in the field of radio astronomy, but also in the spin-off proposals that have already been generated (e.g. the XMM-Newton and Herschel IR space-based telescopes).

螺旋星系被气态光环所包围，它们显示出相当大的结构，并将星系盘内的星际介质（ISM，恒星之间的气体）连接到周围环境中。 有证据表明这些光环是动态实体。也就是说，它们表现出从星系磁盘中驱除灰尘，气体（电离，中性和分子），宇宙射线和磁场。 尚不清楚的是，更有可能显示这样的光晕的星系，又有多少排出的材料循环再次回到磁盘上，以及多少材料离开银河系，富集了银河系介质（IgM，星系之间的低密度气体）。 我们知道，这种流出（或“反馈”）在星系的形成中起着至关重要的作用，但是这项活动的性质和细节并不众所周知。 证据表明，星系进化（包括我们自己的银河系的进化）受到这种活动的强烈影响，但我们甚至不知道这种活动的主要驱动力。 我的建议的目标是回答这些问题。 此外，首次将映射银河系光环中的三维磁场结构，从而回答了有关这些场如何形成的长期问题。为了实现这些目标，我将在新墨西哥州使用扩展的大型阵列（EVLA），这是加拿大 - 墨西哥联合墨西哥射电望远镜的升级，从而导致对先前仪器的灵敏度的数量级提高。 我领导的EVLA提案已获得405个小时的观察时间，以解决上述目标。 与国际合作者团队一起，我们将为Halo研究问题提供明确的答案，并在未来几年中产生真正的遗产价值数据集。 在此过程中，不仅在射电天文学领域，而且在已经产生的衍生提案中（例如，XMM-Newton和Herschel IR基于空间的望远镜）。