Collaborative Research: Chemistry in the Centers of Nearby Galaxies

AST-0506669 Meier分子云是宇宙演化的主要原因，包括恒星诞生、星系合并和活动星系核的燃料。 不幸的是，这种气体主要是分子氢，不容易辐射，因此观测必须依靠更容易检测到的示踪分子，其中最常见的是一氧化碳（CO）。 然而，在最活跃的区域，云化学的变化意味着其他分子可能是更好的示踪剂。 附近星暴星系的单碟光谱显示，星系之间的全球化学差异可能是显着的，这就对使用CO或任何其他单分子作为分子云和气体质量的示踪剂提出了质疑。 该项目将重点研究最近的螺旋星系中心的化学性质，在那里，巨大的分子云可以在线图像中解析，研究至少七种分子并寻找相关性，试图找到云化学的简单特征。这项关于星系化学成像的工作是同类工作中的第一项。 除了揭示这些星系中的天体物理环境外，这项研究可能会限制个别化学反应，识别气相和气体颗粒化学，并致力于研究未来毫米阵列仪器的许多更遥远的星系。

AST-0506669MeierMolecular clouds are responsible for much of the evolution in the Universe, including starbirth, galaxy mergers, and the fueling of active galactic nuclei. Unfortunately, this gas is mostly molecular hydrogen, which does not radiate easily, and so observations must rely on tracer molecules that are more easily detected, the commonest of which is carbon monoxide (CO). However, in the most energetic regions, changes in cloud chemistry mean that other molecules may be better tracers. Single-dish spectra of nearby starburst galaxies show that global chemical differences among galaxies can be significant, which calls into question the use of CO, or, indeed, any other single molecule as a tracer of molecular clouds and gas mass. This project will focus on the chemical properties of the centers of the closest spiral galaxies, where giant molecular clouds can be resolved in line images, studying at least seven molecules and looking for correlations, trying to find simple characterizations of the cloud chemistry.This work on the chemical imaging of galaxies is the first of its kind. In addition to revealing the astrophysical environments in these galaxies, this research may place constraints on individual chemical reactions, identifying gas-phase and gas-grain chemistry, and working towards the study of many, much more distant, galaxies with future millimeter array instruments.