The scaling of galaxy properties with halo mass suggests that feedback loops regulate star formation, but there is no consensus yet about how those feedback loops work. To help clarify discussions of galaxy-scale feedback, Paper I presented a very simple model for supernova feedback that it called the minimalist regulator model. This follow-up paper interprets that model and discusses its implications. The model itself is an accounting system that tracks all of the mass and energy associated with a halo’s circumgalactic baryons—the central galaxy’s atmosphere. Algebraic solutions for the equilibrium states of that model reveal that star formation in low-mass halos self-regulates primarily by expanding the atmospheres of those halos, ultimately resulting in stellar masses that are insensitive to the mass-loading properties of galactic winds. What matters most is the proportion of supernova energy that couples with circumgalactic gas. However, supernova feedback alone fails to expand galactic atmospheres in higher-mass halos. According to the minimalist regulator model, an atmospheric contraction crisis ensues, which may be what triggers strong black hole feedback. The model also predicts that circumgalactic medium properties emerging from cosmological simulations should depend largely on the specific energy of the outflows they produce, and we interpret the qualitative properties of several numerical simulations in light of that prediction.

中文翻译：

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银河系大气的平衡状态。II. 解释和影响


星系属性随光晕质量的缩放表明，反馈回路调节恒星的形成，但关于这些反馈回路如何工作还没有达成共识。为了帮助澄清对星系尺度反馈的讨论，论文 I 提出了一个非常简单的超新星反馈模型，称为极简调节模型。这篇后续论文解释了该模型并讨论了其含义。该模型本身是一个会计系统，用于跟踪与光晕的环银河重子（中心星系的大气层）相关的所有质量和能量。该模型平衡状态的代数解表明，低质量晕中的恒星形成主要通过扩大这些晕的大气层进行自我调节，最终导致恒星质量对银河系风的质量载荷特性不敏感。最重要的是超新星能量与环星系气体耦合的比例。然而，仅靠超新星反馈无法在质量更高的光晕中膨胀银河系大气。根据极简主义调节器模型，大气收缩危机随之而来，这可能是触发强烈黑洞反馈的原因。该模型还预测，从宇宙学模拟中出现的银河系周围介质特性在很大程度上应该取决于它们产生的流出的比能量，我们根据该预测解释了几个数值模拟的定性特性。