We present a novel set of stellar feedback models, implemented in the moving-mesh code arepo, designed for galaxy formation simulations with near-parsec (or better) resolution. These include explicit sampling of stars from the IMF, allowing feedback to be linked to individual massive stars, an improved method for the modelling of H ii regions, photoelectric (PE) heating from a spatially varying FUV field and supernova feedback. We perform a suite of 32 simulations of isolated $M_\mathrm{vir} = 10^{10}\, \mathrm{M_\odot }$ galaxies with a baryonic mass resolution of $20\, \mathrm{M_\odot }$ in order to study the non-linear coupling of the different feedback channels. We find that photoionization (PI) and supernova feedback are both independently capable of regulating star formation to the same level, while PE heating is inefficient. PI produces a considerably smoother star formation history than supernovae. When all feedback channels are combined, the additional suppression of star formation rates is minor. However, outflow rates are substantially reduced relative to the supernova only simulations. We show that this is directly caused by a suppression of supernova clustering by the PI feedback, disrupting star-forming clouds prior to the first supernovae. We demonstrate that our results are robust to variations of our star formation prescription, feedback models and the baryon fraction of the galaxy. Our results also imply that the burstiness of star formation and the mass loading of outflows may be overestimated if the adopted star particle mass is considerably larger than the mass of individual stars because this imposes a minimum cluster size.

中文翻译：

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有效的早期恒星反馈可以通过减少超新星聚集来抑制星系外流

我们提出了一组新颖的恒星反馈模型，在移动网格代码 arepo 中实现，专为具有接近秒差距（或更好）分辨率的星系形成模拟而设计。其中包括来自 IMF 的恒星的显式采样，允许将反馈与单个大质量恒星联系起来，一种改进的 H ii 区域建模方法，来自空间变化的 FUV 场的光电 (PE) 加热和超新星反馈。我们对孤立的 $M_\mathrm{vir} = 10^{10}\, \mathrm{M_\odot }$ 星系进行了一套 32 次模拟，重子质量分辨率为 $20\, \mathrm{M_\odot }$为了研究不同反馈通道的非线性耦合。我们发现光电离 (PI) 和超新星反馈都能够独立地将恒星形成调节到相同的水平，而 PE 加热效率低下。PI 产生的恒星形成历史比超新星要平滑得多。当所有反馈通道组合在一起时，对恒星形成率的额外抑制是次要的。然而，相对于仅超新星的模拟，流出率大大降低。我们表明，这是由 PI 反馈抑制超新星聚集直接引起的，在第一颗超新星之前扰乱了恒星形成的云。我们证明了我们的结果对我们的恒星形成处方、反馈模型和星系重子分数的变化是稳健的。我们的结果还暗示，如果采用的恒星粒子质量远大于单个恒星的质量，那么恒星形成的突发性和流出的质量负载可能被高估，因为这会限制最小的星团大小。