Collaborative Research: Gaseous Halos of Nearby Galaxies as Clues to Galaxy Evolution

兰德博士和沃尔特沃斯博士将在附近数十个边缘螺旋星系的中面以外寻找温暖的电离和中性气体。这种弥散的气体在圆盘的赤道平面上比密度更大的冷却气体旋转得更慢；这种滞后仍然不被理解，并可能掌握气体起源的线索。该团队将使用ARC 3.5米望远镜的新多缝模式来测量这种气体在7个恒星形成旺盛的星系和2个恒星诞生速率较低的边缘星系中的电离氢发射线。他们还将利用国家射电天文台的甚大阵列完成和分析B和C阵列中观察到的四个星系在21厘米中性氢谱线上的地图，并将使用荷兰的韦斯特博克阵列对另外八个星系进行深入观测。这些“数据立方体”中的速度信息将被用来区分离开平面的气体与翘曲或其他结构，并确定其旋转。目的是利用速度信息来确定离开平面的气体是新坠入恒星形成盘，还是已经从恒星形成盘喷出。这项研究将构成两篇博士论文的基础。新墨西哥大学和新墨西哥州立大学都是为西语裔服务的机构，新墨西哥州立大学的天文学家在公共宣传方面尤其积极。

Dr Rand and Dr. Walterbos will search for warm ionized and neutral gas away from the mid-plane of a couple of dozen nearby edge-on spiral galaxies. This diffuse gas rotates more slowly than the denser cool gas in the equatorial plane of the disk; this lag is still not understood, and may hold a clue to the origin of the gas. The team will use the new multi-slit mode of the ARC 3.5-m telescope to measure emission lines of ionized hydrogen from this gas in 7 edge-on galaxies that have vigorous star formation and two with lower rates of starbirth. They will also complete and analyze maps in the 21cm line of neutral hydrogen for four galaxies observed in B and C arrays with the National Radio Astronomy Observatory's Very Large Array, and will use the Westerbork array in the Netherlands to make deep observations for a further eight galaxies. The velocity information in these 'data cubes' will be used to distinguish off-plane gas from a warp or other structure, and to determine its rotation. The aim is to use the velocity information to determine whether the off-plane gas is newly falling in, or has been ejected from the star-forming disk. This research would form the basis for two PhD theses. Both the University of New Mexico and New Mexico State University are Hispanic-serving institutions, and the astronomers at New Mexico State University are particularly active in public outreach.