Collaborative Research: The Magellanic Clouds as a Laboratory for Star Formation at Low Metallicity

这些天文学家试图了解是什么导致太空中的气体云坍塌形成恒星。直接的原因是地心引力，但为什么重力在一些云层上作用迅速，而在另一些云层上作用缓慢，这仍然是一个谜。研究人员计划通过对附近两个卫星星系麦哲伦星云中的气体云进行详细观测来解开这个谜团。这些观测是由美国国家科学基金会的阿塔卡马大毫米/亚毫米阵列(ALMA)天文台进行的，将具有测量气体性质所需的质量和细节。研究人员将把对恒星环境的测量与年轻恒星的位置和年龄进行比较。研究人员来自三所不同的大学，每所大学都将为培养下一代科学家做出贡献。学生将在科学数据分析和仪器技术方面获得实践经验。该团队将开发新的虚拟现实工具，以提高公众对科学的理解。随着ALMA前所未有的敏感性和对南方天空的访问，天文学家们开始解析麦哲伦云中分子云的块状、丝状结构。分析表明，在给定的尺度上，分子气体的速度色散随着星云的整体恒星形成活动而增加，这表明来自年轻恒星的能量反馈在维持云内的湍流运动方面发挥了重要作用。然而，其他证据，包括我们的发现，团块和细丝通常在边缘上不稳定到崩溃，支持这样的观点，即速度分散增加和恒星形成都可以由引力不稳定驱动。研究人员计划进行观测，以揭示恒星形成的条件。他们将使用一种广泛的、基于调查的方法，这种方法可以识别缺乏关键成分之一的区域(例如，年轻的恒星或稠密的气体)，从而更准确地区分因果关系。将ALMA在亚秒尺度上对分子气体的成像与对这些星系中年轻恒星群体的红外测量相结合，将为触发、反馈和云条件在恒星形成过程中的作用提供新的见解。这一奖项反映了NSF的法定任务，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。

These astronomers seek to understand what causes clouds of gas in space to collapse to form stars. The immediate cause is the force of gravity, but why gravity acts quickly on some clouds and slowly in others remains a puzzle. The investigators have a plan to solve this puzzle by using detailed observations of gas clouds located in two nearby satellite galaxies, the Magellanic Clouds. The observations, taken with NSF’s Atacama Large Millimeter/submillimeter Array’s (ALMA) observatory, will have the quality and detail needed to measure the properties of the gas. The investigators will compare measurements of the stellar environment with the locations and ages of young stars. The investigators are from three different universities, and each will contribute to training of next generation scientists. The students will get hands-on experience in the techniques of scientific data analysis and instrumentation. The team will develop of new virtual reality tools for improving the public understanding of science.With the ALMA’s unprecedented sensitivity and access to the southern sky, astronomers are beginning to resolve the clumpy, filamentary structure of molecular clouds in the Magellanic Clouds. Analysis has shown that the velocity dispersion of the molecular gas at a given scale increases with the overall star formation activity of the cloud, suggesting that energetic feedback from young stars plays a significant role in maintaining turbulent motions within the cloud. However, other lines of evidence, including our finding that clumps and filaments are typically marginally unstable to collapse, support the view that increased velocity dispersion and star formation can both be driven by gravitational instability. The investigators plan observations to reveal the conditions for star formation. They will use a broad, survey-based, approach which can identify regions deficient in one of the key ingredients (e.g., young stars or dense gas) and thus more accurately distinguish cause and effect. Combining ALMA imaging of the molecular gas on sub-parsec scales with infrared surveys of the young stellar populations in these galaxies will provide new insights into the roles of triggering, feedback, and cloud conditions in the star formation process.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.