The CODEX of the Milky Way

恒星是像我们银河系这样的星系的基本组成部分。 要了解星系的演化，乃至宇宙的历史，需要彻底了解不同类型的恒星如何随时间变化。 恒星有自己的生命周期，从恒星在冷云中诞生，到它们成熟为我们在夜晚看到的恒星，再到它们最终成为红巨星或有时是壮观的超新星。然而，恒星的形成过程仍然知之甚少，主要是由于难以观察在可见光无法穿透的寒冷黑暗分子云中发生的过程。 相反，天文学家使用更长波长的辐射，如红外光或无线电波，来发现星星形成的重要细节，包括形成分子所需的元素的温度，密度和丰度。 研究人员将以一种引人注目的方式与公众分享他们的研究，通过向学童发起“科学+艺术”的外展活动，强调科学与艺术之间的重要联系，以获得公众的欣赏，并增加这项研究的影响。研究人员研究的一个主要目标是测试银河系中分子发射的模型，基于云层中一氧化碳（CO）分子的毫米波发射图。 天文学家对银河系进行CO观测是因为这种分子分布广泛，相对容易观测。 研究人员最近发表的研究表明，对CO映射的简单解释可能会微妙地误导我们对云的物理条件的理解，云主要由分子氢（H2）组成，很难直接检测到。 简而言之，CO图在追踪H2时可能有偏差。研究人员将完成并向社区发布他们的银河系分子线调查，作为银河系致密气体和激发组合图集（CODEX）。 此外，他们将提供一个更复杂的计算分子云的物理条件，这是以前没有尝试过的，除了在小得多的尺度。 这将使天文学家能够更好地了解H2分子如何在引力的影响下组装，从而在整个银河系中形成恒星，并延伸到其他螺旋星系。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Stars are the basic building blocks of galaxies like our own Milky Way. Understanding galaxy evolution, and indeed the history of the universe, requires a thorough understanding of how different types of stars change with time. Stars have their own life cycle, from stellar birth in cold clouds, through their maturity as the stars we see at night, to their ends as red giants or sometimes spectacular supernovae. The process of forming stars, however, is still poorly understood, mainly due to the difficulty in observing the processes that take place inside cold, dark molecular clouds which visible light cannot penetrate. Instead, astronomers use longer-wavelength radiation, like infrared light or radio waves, to discover important details of star formation, including the temperature, density and abundances of elements that are needed to form molecules. The investigator will share their research with the public in a striking way, by launching a “science+art” outreach effort to schoolchildren, emphasizing the important connections between science and art for the general public's appreciation, and increasing the impact of this research.A primary goal of the investigator’s research is testing models for molecular emission in the galaxy, based on maps of mm-wave emission from carbon monoxide (CO) molecules in clouds. Astronomers make CO observations of the Milky Way because the molecule is widespread and relatively easy to observe. The investigator has recently published research suggesting simple interpretations of CO mapping may be subtly misleading our understanding of the physical conditions in clouds, which are mostly made up of molecular hydrogen (H2) that is very difficult to detect directly. In short, the CO maps can be biased in tracing H2. The investigator will complete and release to the community their molecular line survey of the Milky Way as the Combined Dense Gas and Excitation Atlas of the Milky Way (the CODEX). In addition, they will provide a more sophisticated calculation of the physical conditions in molecular clouds, something which has not been attempted before excepting on much smaller scales. This will allow astronomers to better understand how the H2 molecules assemble under the influence of gravity to make stars throughout the Milky Way, and by extension, in other spiral galaxies.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.