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

巨分子云是旋涡星系中星星形成和星系演化的重要因素。该项目将利用阿尔马射电望远镜的高分辨率观测来绘制M83 --一个附近的螺旋星系--中的CO气体含量。这些观测将识别这个星系中的每一个GMC，最低质量为10，000太阳质量。这张地图将为GMC、星星形成、旋臂和星系演化之间的联系提供新的见解。该项目还将开发和支持用于大学课程教育的无线电仪器，该项目将对M83整个盘上的大量分子气体进行无偏普查，解决GMC分布，标度关系，质量函数及其空间变化。它将描述整个盘上每个GMC的CO 2-1/1-0线比，并研究其作为星系结构和星星形成活动的函数的变化。同时分析整个星系盘的CO（1-0）和CO（2-1），将为今后研究星系ISM演化提供独特的参考。该项目将更新和重新设计一个教育无线电干涉仪，供大学课程使用。此次升级的一部分将是将工作频率转移到受保护的研究频段。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值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.