The Inner Workings of Starbursts and Their Winds

自20世纪90年代中期以来，天文学家已经意识到宇宙中星星的形成并不是恒定的，事实上，每单位体积的星星形成率在z ~ 2达到峰值后一直在稳步下降。虽然还没有完全理解，但这被认为是由于来自宇宙网的原始气体流入量的稳定减少，过去星星形成的更有效模式，以及来自强烈星星形成区域的大规模星系风的影响。本研究集中在高空间分辨率亚/毫米波长线和连续观测本地星暴星系，其中发生高效率星星形成和相关的风驱动外流，以便更好地了解驱动星星形成的物理过程在其高峰时期（即，“宇宙正午”）。该项目将支持两名研究生和一名本科生，后者参与一个旨在提高少数民族人口参与STEM的副项目。该项目将利用对本地星暴星系NGC 253，M82和NGC 4945的高角分辨率亚毫米和射电观测，推进对塑造它们演化的物理过程的认识。这项研究的一个关键目标是更好地理解星星形成的物理学“淬火”通过（例如）在观测上限制了由恒星爆发驱动的星系尺度风驱动外流中冷气体的夹带，以及外流气体中影响其命运的物理条件。该研究小组还将测量年轻的大质量星爆星系团的基本性质，提高我们对其中形成的恒星比例的认识，并确定分子气体性质在星爆星系中的变化。所有这些结果将导致星系演化的物理上更现实的数值模型。研究人员将把这些结果放在宇宙星星形成的高峰期的主序星星系的背景下，通过比较新的大星系样本中局部恒星爆发的物理状态和空间分辨的分子特性。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。

Astronomers have realized since the mid-1990s that the star formation in the Universe has not been constant, and that in fact, the star formation rate per unit volume has steadily decreased since attaining a peak at z ~ 2. While still not completely understood, this is thought to be due to a combination of a steady decrease in the inflow of pristine gas from the Cosmic Web, a more efficient mode of star formation in the past, and the effects of large-scale galactic winds from regions of intense star formation. This research centers on high spatial resolution sub/millimeter wavelength line and continuum observations of local starburst galaxies, where high efficiency star formation and associated wind-driven outflows occur, in order to better understand the physical processes driving star formation at its peak epoch (i.e., "cosmic noon"). This project will support two research graduate students and one undergraduate student, the latter participating in a side project working to increase STEM participation among minority populations.Using high angular resolution sub/millimeter and radio observations of the local starburst galaxies NGC 253, M82, and NGC 4945, this project will advance knowledge of the physical processes that shape their evolution. A key goal of this research is a better understanding of the physics of star formation “quenching" through (e.g.) observationally constraining the entrainment of cold gas in galactic scale wind-driven outflows powered by starbursts and the physical conditions in the outflowing gas that influence its fate. The research team will also measure basic properties of young, massive starburst clusters and improve our knowledge of the fraction of stars that form in them and determine how molecular gas properties vary among starburst galaxies. All these results will lead to more physically realistic numerical models of galaxy evolution. The researchers will place these results in the context of main sequence galaxies at the peak of cosmic star formation by comparing the physical state of the local starbursts with spatially resolved molecular properties in a new large galaxy sample (DYNAMO).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.