Variations in the slope of the resolved star-forming main sequence: a tool for constraining the mass of star-forming regions
Variations in the slope of the resolved star-forming main sequence: a tool for constraining the mass of star-forming regions
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DOI：
10.1093/mnrasl/slaa013
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发表时间：
2019-12
影响因子：
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通讯作者：
M. Hani;C. Hayward;Matthew E. Orr;S. Ellison;P. Torrey;N. Murray;A. Wetzel;C. Faucher-Giguère
中科院分区：
文献类型：
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作者：
M. Hani;C. Hayward;Matthew E. Orr;S. Ellison;P. Torrey;N. Murray;A. Wetzel;C. Faucher-Giguère
星系的整体恒星质量和恒星形成速率（“恒星形成主序”，简称SFMS）之间的相关性是一个公认的尺度关系。最近，调查发现了kpc和亚kpc尺度（“分辨SFMS”，rSFMS）上恒星形成速率（SFR）与恒星质量表面密度之间的关系。在这项工作中，我们证明了rSFMS在反馈现实环境2 （FIRE-2）对银河系质量星系的放大模拟中自然出现。我们在各种空间分辨率和恒星形成平均时间尺度下制作模拟星系的SFR和恒星质量图，并使用文献中的多种方法拟合rSFMS。而SFMS斜率（αMS）的绝对值取决于拟合方法，无论采用何种拟合方法，当恒星形成时间尺度越长、空间分辨率越低时，其斜率越陡。我们提出了一个玩具模型，定量地捕捉了模拟星系α质谱对空间分辨率的依赖关系，并用它来说明这种依赖关系如何被用来约束恒星形成团块的特征质量。
The correlation between galaxies’ integrated stellar masses and star formation rates (the ‘star formation main sequence’, SFMS) is a well-established scaling relation. Recently, surveys have found a relationship between the star formation rate (SFR) and stellar mass surface densities on kpc and sub-kpc scales (the ‘resolved SFMS’, rSFMS). In this work, we demonstrate that the rSFMS emerges naturally in Feedback In Realistic Environments 2 (FIRE-2) zoom-in simulations of Milky Way-mass galaxies. We make SFR and stellar mass maps of the simulated galaxies at a variety of spatial resolutions and star formation averaging time-scales and fit the rSFMS using multiple methods from the literature. While the absolute value of the SFMS slope (αMS) depends on the fitting method, the slope is steeper for longer star formation time-scales and lower spatial resolutions regardless of the fitting method employed. We present a toy model that quantitatively captures the dependence of the simulated galaxies’ αMS on spatial resolution and use it to illustrate how this dependence can be used to constrain the characteristic mass of star-forming clumps.