Collaborative Research: Non-thermal Radio Halos of Spiral Galaxies as Clues to Galaxy Evolution

合作研究：螺旋星系的非热射电晕作为星系演化的线索

• 批准号: 1615594
• 负责人: Rene Walterbos
• 金额: $ 18.71万
• 依托单位: New Mexico State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1615594&HistoricalAwards=false
• 关键词: Collaborative; Research; Non; thermal; Radio

To understand how stars like the Sun and planets like Earth came to be, we must understand how galaxies, such as our Milky Way, form and evolve. This project is an attempt to understand how interstellar gas and energetic particles are ejected from galaxy disks, where most of the gas and stars are found, and interact with the galaxy halo. This cyclical process is important for understanding how star formation proceeds in galaxies, and the rate at which galaxies grew when they were forming. The study makes use of radio images from the NSF-funded Karl G. Jansky Very Large Array (VLA) and the Green Bank Telescope (GBT), optical data from the Apache Point 3.5-meter telescope, as well as archival infrared data. The project will provide opportunities for two PhD student theses at Hispanic Serving Institutions, and the PIs will also contribute to a training program run by the National Radio Astronomy Observatory for faculty at small colleges.Galaxy growth and evolution depend on both the acquisition of gas from the galaxy environment and energetic outflows from disks. The detailed physics of these processes needs to be understood, and nearby edge-on galaxies are the best objects where it is possible to cleanly separate disk and halo components. The project leverages a major new survey of radio continuum emission from edge-on galaxies called CHANG-ES (Continuum Halos in Nearby Galaxies: an EVLA Survey). The first goal is to further our understanding of the dynamics of disk-halo flows by assessing the role of non-thermal gas pressure gradients in galaxy halos, using radio maps made from the VLA and GBT. The second goal focuses on identifying sites of cosmic ray (CR) injection and propagation into galaxy halos. For this, the spatial variation of the non-thermal spectral index will be mapped, after robustly separating thermal and non-thermal radio emission using CHANG-ES maps in conjunction with infrared data and H-alpha images. The third science goal is to examine the connection between CR outflows and disk-halo cycling of thermal gas, and whether this relation depends on factors such as star formation rate.

为了理解像太阳这样的恒星和像地球这样的行星是如何形成的，我们必须了解星系，比如我们的银河系，是如何形成和演化的。该项目试图了解星际气体和高能粒子如何从星系盘（发现大多数气体和恒星的地方）喷射出来，并与星系晕相互作用。 这个周期性的过程对于理解星系中星星的形成过程以及星系形成时的生长速度非常重要。 这项研究利用了美国国家科学基金会资助的卡尔G。Jansky甚大阵列（VLA）和绿色银行望远镜（GBT），阿帕奇点3.5米望远镜的光学数据，以及档案红外数据。 该项目将为西班牙裔服务机构的两名博士生论文提供机会，PI还将为国家射电天文台为小型学院的教师举办的培训计划做出贡献。星系的增长和演化取决于从星系环境中获得气体和从磁盘中流出的能量。需要了解这些过程的详细物理过程，而附近的边缘星系是最好的对象，在那里可以干净地分离盘和晕组件。该项目利用了一项名为CHANG-ES（邻近星系的连续晕：EVLA调查）的边缘星系无线电连续辐射的重大新调查。第一个目标是通过评估非热气体压力梯度在星系晕中的作用，利用VLA和GBT制作的射电图，进一步了解盘晕流的动力学。 第二个目标的重点是确定宇宙射线（CR）注入和传播到星系晕的网站。 为此，在使用CHANG-ES地图结合红外数据和H-alpha图像有力地分离热和非热无线电发射之后，将绘制非热光谱指数的空间变化。 第三个科学目标是检查CR流出和热气体的盘晕循环之间的联系，以及这种关系是否取决于星星形成率等因素。