Spatial Decorrelation of Young Stars and Dense Gas as a Probe of the Star Formation-Feedback Cycle in Galaxies
Vadim A. Semenov, Andrey V. Kravtsov, Nickolay Y. Gnedin
备注：
21 pages + appendix, 17 figures; published in ApJ; the animated version of Figure 1 is available in the online version of the article and at https://vadimsemenov.com/research/ngc300
The spatial decorrelation of dense molecular gas and young stars observed on $\lesssim 1$ kiloparsec scales in nearby galaxies indicates rapid dispersal of star-forming regions by stellar feedback. We explore the sensitivity of this decorrelation to different processes controlling the structure of the interstellar medium, the abundance of molecular gas, star formation, and feedback in a suite of simulations of an isolated dwarf galaxy with structural properties similar to NGC300 that self-consistently model radiative transfer and molecular chemistry. Our fiducial simulation reproduces the magnitude of decorrelation and its scale dependence measured in NGC300, and we show that this agreement is due to different aspects of feedback, including H$_2$ dissociation, gas heating by the locally variable UV field, early mechanical feedback, and supernovae. In particular, early radiative and mechanical feedback affects the correlation on $\lesssim 100$ pc scales, while supernovae play a significant role on $\gtrsim 100$ pc scales. The correlation is also sensitive to the choice of the local star formation efficiency per freefall time, $ε_{\rm ff}$, which provides a strong observational constraint on $ε_{\rm ff}$ when the global star formation rate is independent of its value. Finally, we explicitly show that the degree of correlation between the peaks of molecular gas and star formation density is directly related to the distribution of the lifetimes of star-forming regions.
Blowing star formation away in AGN hosts (BAH) -- V: The Feeding-Feedback Cycle in local AGNs as revealed by their stellar populations
Universidade Federal do Rio Grande do Sul（南里奥格兰德联邦大学）；Universidade Federal de Santa Maria（圣玛丽亚联邦大学）；Johns Hopkins University（约翰斯·霍普金斯大学）；Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Universidad de La Laguna（拉帕鲁纳大学）
Live Fast, Die Young: GMC lifetimes in the FIRE cosmological simulations of Milky Way-mass galaxies
我们提出的第一个测量的宇宙学模拟中的巨型分子云（GMC）的寿命在$z = 0$，使用的LATTE套件的银河系质量的星系的FIRE-2模拟。我们跟踪GMC与总气体质量$\gtrsim 10^5$ M $_\odot$在高空间（$\sim1$ pc），质量（$7100$ M $_{\odot}$），和时间（1百万年）的分辨率。我们模拟的GMCs与银河系和邻近星系中大质量GMCs的质量分布是一致的。我们发现了$5-7$ Myr的GMC寿命，或者平均1-2次自由落体时间，只有不到2个$\%$的云寿命超过2000万年。我们发现GMC寿命随维里参数的增加而减小，随银河系中心半径的增加而微弱增加，这意味着环境影响GMC的演化周期。然而，我们的GMC寿命没有显示出对GMC质量或恒星形成量的系统依赖性。这些结果与文献中的推论基本一致，并提供了一个初步的调查，最终了解的物理过程，管理GMC寿命在宇宙学设置。
Mass regulates the emerging timescale of young star clusters
Stockholm University（斯德哥尔摩大学）；University of Massachusetts（马萨诸塞大学）；Queen Mary University of London（伦敦玛丽女王大学）；Australian National University（澳大利亚国立大学）；University of Arizona（亚利桑那大学）；Space Telescope Science Institute（太空望远镜科学研究所）
From Young to Older Disks: JWST/MIRI Evidence for Fading Molecular Emission and Hints for Elevated C/O in Upper Scorpius
The University of Arizona（亚利桑那大学）；Peking University（北京大学）；NASA Ames Research Center（NASA艾姆斯研究中心）；SETI Institute（SETI研究所）；Texas State University（德克萨斯州立大学）；University of Leeds（利兹大学）；California Institute of Technology（加州理工学院）；Joint ALMA Observatory（ALMA联合天文台）；Chinese Academy of Sciences（中国科学院）
