An uncertainty principle for star formation - II. A new method for characterizing the cloud-scale physics of star formation and feedback across cosmic history
An uncertainty principle for star formation - II. A new method for characterizing the cloud-scale physics of star formation and feedback across cosmic history
复制标题
DOI：
10.1093/mnras/sty1128
复制
发表时间：
2018-04
影响因子：
4.8
通讯作者：
J. Kruijssen;A. Schruba;A. Hygate;Chia-Yu Hu;D. Haydon;S. N. L. Heidelberg;Mpia;Mpa;Mpe;Cca;Ljmu
中科院分区：
文献类型：
--
作者：
J. Kruijssen;A. Schruba;A. Hygate;Chia-Yu Hu;D. Haydon;S. N. L. Heidelberg;Mpia;Mpa;Mpe;Cca;Ljmu
星星形成和反馈的云尺度物理是星系形成研究中的主要不确定性。在地方小组的有限环境之外，经验上的限制因素有限，阻碍了进展。特别是，分子云生命周期，星星形成和反馈的量化不佳的时间演化阻碍了强大的预测规模小于盘尺度的高度，解决了现代星系形成模拟。我们提出了一种新的统计方法来推导分子云和恒星形成区的演化时间轴。通过量化气体或星星形成示踪剂排放峰值周围的气体-恒星通量比的过剩或不足，我们直接测量这些峰值的相对稀有性，这使我们能够推导出它们的寿命。我们提出了一个一步一步的，定量描述的方法，并证明其实际应用。该方法的准确性进行了测试，在近300个实验中使用模拟星系地图，表明它是能够约束的分子云的寿命和反馈时间尺度为$<0.1$ dex精度。对演化时间轴的访问提供了各种附加物理量，诸如云尺度星星形成效率、反馈流出速度、质量加载因子以及反馈能量或动量与环境介质的耦合效率。我们表明，结果是强大的各种气体和星星形成示踪剂，空间分辨率，星系倾角和星系的大小。最后，我们证明了我们的方法可以应用于高红移（$z\lesssim4$），并且在当前大型天文台上进行可行的时间投资。这是一个重大转变，从以前的研究，限制了物理学的星星形成和反馈在太阳附近。
The cloud-scale physics of star formation and feedback represent the main uncertainty in galaxy formation studies. Progress is hampered by the limited empirical constraints outside the restricted environment of the Local Group. In particular, the poorly-quantified time evolution of the molecular cloud lifecycle, star formation, and feedback obstructs robust predictions on the scales smaller than the disc scale height that are resolved in modern galaxy formation simulations. We present a new statistical method to derive the evolutionary timeline of molecular clouds and star-forming regions. By quantifying the excess or deficit of the gas-to-stellar flux ratio around peaks of gas or star formation tracer emission, we directly measure the relative rarity of these peaks, which allows us to derive their lifetimes. We present a step-by-step, quantitative description of the method and demonstrate its practical application. The method's accuracy is tested in nearly 300 experiments using simulated galaxy maps, showing that it is capable of constraining the molecular cloud lifetime and feedback time-scale to $<0.1$ dex precision. Access to the evolutionary timeline provides a variety of additional physical quantities, such as the cloud-scale star formation efficiency, the feedback outflow velocity, the mass loading factor, and the feedback energy or momentum coupling efficiencies to the ambient medium. We show that the results are robust for a wide variety of gas and star formation tracers, spatial resolutions, galaxy inclinations, and galaxy sizes. Finally, we demonstrate that our method can be applied out to high redshift ($z\lesssim4$) with a feasible time investment on current large-scale observatories. This is a major shift from previous studies that constrained the physics of star formation and feedback in the immediate vicinity of the Sun.