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原因导致太空中的气体云坍缩形成恒星。 直接原因是重力，但为什么重力对某些云的作用很快，而对另一些云的作用很慢，这仍然是一个谜。 研究人员计划通过对位于附近两个卫星星系麦哲伦云中的气体云进行详细观测来解决这个难题。由NSF的阿塔卡马大型毫米/亚毫米阵列（阿尔马）天文台进行的观测将具有测量气体性质所需的质量和细节。 研究人员将比较恒星环境的测量结果与年轻恒星的位置和年龄。 研究人员来自三所不同的大学，每一所大学都将为培养下一代科学家做出贡献。学生将获得科学数据分析和仪器技术的实践经验。 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。凭借阿尔马前所未有的灵敏度和对南方天空的访问，天文学家们开始解析麦哲伦星云中分子云的clusional，非结构性结构。分析表明，在给定的尺度下，分子气体的速度色散随着云的整体星星形成活动的增加而增加，这表明来自年轻恒星的能量反馈在维持云内的湍流运动中起着重要作用。 然而，其他证据，包括我们发现的团块和细丝通常在崩溃时稍微不稳定，支持这样的观点，即速度色散的增加和星星的形成都可以由引力不稳定性驱动。 研究人员计划观测以揭示星星形成的条件。 他们将使用一种广泛的、以调查为基础的方法，这种方法可以确定缺乏一种关键成分的地区（例如，年轻的恒星或致密气体），从而更准确地区分因果关系。 结合阿尔马成像的分子气体在亚秒差距尺度与红外调查的年轻恒星群体在这些星系将提供新的见解触发，反馈和云的条件在星星形成过程中的作用。这一奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

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.