Mapping Molecular ISM in the Whole Disk of the Barred Spiral Galaxy M83

巨型分子云(GMC)是螺旋星系恒星形成和演化的重要因素。该项目将使用ALMA射电望远镜的高分辨率观测来绘制M83--附近的螺旋星系--中的CO气体含量。这些观测将确定这个星系中的每一个GMC，小到10000个太阳质量的最低质量。这张地图将提供关于GMC、恒星形成、旋臂和星系演化之间的联系的新见解。该项目还将开发和支持大学课程中用于教育的无线电仪器。该项目将对M83整个圆盘上的大分子气体进行无偏见的普查，解决GMC的分布、标度关系、质量函数及其空间变化。它将表征每个GMC在整个盘面上的CO2-1/1-0线比，并研究其随星系结构和恒星形成活动的变化。对整个盘面上CO(1-0)和CO(2-1)的同时分析将为今后星系ISM演化的研究提供独特的参考。该项目将升级和重新设计一种用于大学课程的教育无线电干涉仪。此次升级的一部分将是将工作频率转移到一个受保护进行研究的频段。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Giant molecular clouds (GMCs) are an important factor in star formation in spiral galaxies and in the evolution of those galaxies. This project will use high resolution observations from the ALMA radio telescope to map out the CO gas content in M83 -- a nearby spiral galaxy. These observations will identify every GMC in this galaxy down to the lowest masses of 10,000 solar masses. This map will provide new insights on the connection between GMCs, star formation, spiral arms, and galaxy evolution. The project will also develop and provide support for radio instruments for educational uses in university courses.The project will take an unbiased census of the bulk molecular gas over the whole disk of M83, resolving the GMC distribution, scaling relations, mass function, and their spatial variations. It will characterize the CO 2-1/1-0 line ratio of every GMC over the whole disk and investigate its variations as a function of galactic structures and star formation activity. The simultaneous analysis of CO(1-0) and CO(2-1) over the entire disk will provide unique reference for future studies of ISM evolution in galaxies. The project will upgrade and redesign an educational radio interferometer for use in university courses. Part of this upgrade will be to shift the operating frequency to a band that is protected for research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.