The nature of galactic spiral arms in disc galaxies remains elusive. Regardless of the spiral model, arms are expected to play a role in sculpting the star-forming interstellar medium. As such, different arm models may result in differences in the structure of the interstellar medium and molecular cloud properties. In this study we present simulations of galactic discs subject to spiral arm perturbations of different natures. We find very little difference in how the cloud population or gas kinematics vary between the different grand-design spirals, indicting that the interstellar medium on cloud scales cares little about where spiral arms come from. We do, however, see a difference in the interarm/arm mass spectra, {and minor differences in tails of the distributions of cloud properties} (as well as radial variations in the stellar/gaseous velocity dispersions). These features can be attributed to differences in the radial dependence of the pattern speeds between the different spiral models, and could act as a metric of the nature of spiral structure in observational studies.

中文翻译：

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不同的螺旋臂模型如何影响 ISM 和 GMC 种群？

盘状星系中星系旋臂的性质仍然难以捉摸。不管螺旋模型如何，预计臂将在塑造恒星形成的星际介质中发挥作用。因此，不同的臂模型可能会导致星际介质结构和分子云特性的差异。在这项研究中，我们展示了受不同性质的旋臂扰动影响的星系盘的模拟。我们发现不同大设计螺旋之间的云种群或气体运动学差异很小，这表明云尺度上的星际介质很少关心螺旋臂的来源。然而，我们确实看到了臂间/臂质谱的差异，{和云特性分布尾部的微小差异}（以及恒星/气态速度弥散的径向变化）。这些特征可归因于不同螺旋模型之间模式速度的径向依赖性的差异，并且可以作为观测研究中螺旋结构性质的度量。