An Empirical Determination of the Dependence of the Circumgalactic Mass Cooling Rate and Feedback Mass Loading Factor on Galactic Stellar Mass
An Empirical Determination of the Dependence of the Circumgalactic Mass Cooling Rate and Feedback Mass Loading Factor on Galactic Stellar Mass
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DOI：
10.3847/1538-4357/ac0433
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发表时间：
2021-04
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影响因子：
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通讯作者：
H. Zhang 张;D. Zaritsky;K. Olsen;P. Behroozi;J. Werk;R. Kennicutt;Lizhi 利智 Xie 谢;X. Yang 杨;T. Fang 方;G. De Lucia;M. Hirschmann;F. Fontanot
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作者：
H. Zhang 张;D. Zaritsky;K. Olsen;P. Behroozi;J. Werk;R. Kennicutt;Lizhi 利智 Xie 谢;X. Yang 杨;T. Fang 方;G. De Lucia;M. Hirschmann;F. Fontanot
利用我们对起源于星系晕中冷气体（T = 104 K）的Hα发射线通量的测量，建立了一个描述冷环星系介质（CGM）质量与星系恒星质量（109.5<M <$/M <$<1011）和环境关系的联合模型.由于Hα辐射与这种气体的主要冷却通道相关，我们能够估计CGM冷却并成为中央星系中星星形成燃料的速率。我们描述了这种计算，它使用我们的观察，以前的测量一些关键的CGM属性，并使用多云建模套件的冷却机制建模。我们发现，质量冷却率是大于星星形成率的中心星系的一个因素的104 -90，经验证实，有足够的燃料来解决气体消耗的问题，需要反馈，以避免收集太多的冷气体在星系。我们发现我们的估计质量冷却速率和质量加载因子和独立的理论研究的预测之间非常吻合。我们从几种完全不同的处理方法中发现的结果的收敛，特别是在银河系质量范围的低端，是一个强有力的迹象，表明我们对反馈在这个质量范围内的定量影响有了相对可靠的理解。
Using our measurements of the Hα emission line flux originating in the cool (T ∼ 104 K) gas that populates the halos of galaxies, we build a joint model to describe the mass of the cool circumgalactic medium (CGM) as a function of galactic stellar mass ( 109.5<M∗/M⊙<1011 ) and environment. Because the Hα emission correlates with the main cooling channel for this gas, we are able to estimate the rate at which the CGM cools and becomes fuel for star formation in the central galaxy. We describe this calculation, which uses our observations, previous measurements of some critical CGM properties, and modeling of the cooling mechanism using the Cloudy modeling suite. We find that the mass cooling rate is larger than the star formation rates of the central galaxies by a factor of ∼4–90, empirically confirming that there is sufficient fuel to resolve the gas consumption problem and that feedback is needed to avoid collecting too much cold gas in galaxies. We find excellent agreement between our estimates of both the mass cooling rates and mass loading factors and the predictions of independent theoretical studies. The convergence in results that we find from several completely different treatments of the problem, particularly at the lower end of the galactic mass range, is a strong indication that we have a relatively robust understanding of the quantitative effects of feedback across this mass range.