Equilibrium model constraints on baryon cycling across cosmic time
Equilibrium model constraints on baryon cycling across cosmic time
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DOI：
10.1093/mnras/stv1387
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发表时间：
2014-11
影响因子：
4.8
通讯作者：
Sourav Mitra;R. Dav'e;K. Finlator
中科院分区：
文献类型：
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作者：
Sourav Mitra;R. Dav'e;K. Finlator
星系通过来自恒星、超新星和黑洞的能量反馈强烈地自我调节它们的生长，但这些过程是星系形成理论中最不了解的方面。我们提出了一个分析的星系演化模型，直接约束这样的反馈过程从观测到的星系尺度关系。平衡模型，这是广泛适用于恒星形成的中央星系主导宇宙星星的形成，是基于一个假设，即星系生活在一个缓慢演变的平衡之间的流入，流出，和星星的形成。使用贝叶斯蒙特卡罗马尔可夫链方法，我们约束我们的模型，以匹配观测到的恒星质量和晕质量，星星形成率，金属丰度从0<z<2之间的星系标度关系。使用8个自由参数可以实现良好的拟合（卡方系数x ^2 ~1.6）。我们进一步表明，将我们的模型约束到三个数据集中的任何两个数据集也会产生与第三个数据集的拟合，该拟合在合理的系统不确定性范围内。由此产生的描述重子循环的最佳拟合参数表明，银河系外流尺度介于能量和动量驱动的风之间，风回收时间对质量的依赖性较弱，以及随着红移适度向上演化的猝灭质量尺度。该模型进一步预测了恒星质量-恒星形成率关系，与z~6的观测结果吻合得很好。我们的研究结果表明，这个简单的分析框架捕获的基本物理过程所需的模型的平均演化的恒星和金属在星系中，尽管没有纳入许多典型的成分星系形成模型，如合并或磁盘形成。
Galaxies strongly self-regulate their growth via energetic feedback from stars, supernovae, and black holes, but these processes are among the least understood aspects of galaxy formation theory. We present an analytic galaxy evolution model that directly constrains such feedback processes from observed galaxy scaling relations. The equilibrium model, which is broadly valid for star-forming central galaxies that dominate cosmic star formation, is based on the ansatz that galaxies live in a slowly-evolving equilibrium between inflows, outflows, and star formation. Using a Bayesian Monte Carlo Markov chain approach, we constrain our model to match observed galaxy scaling relations between stellar mass and halo mass, star formation rate, and metallicity from 0<z<2. A good fit (chi^2~1.6) is achieved with eight free parameters. We further show that constraining our model to any two of the three data sets also produces a fit to the third that is within reasonable systematic uncertainties. The resulting best-fit parameters that describe baryon cycling suggest galactic outflow scalings intermediate between energy and momentum-driven winds, a weak dependence of wind recycling time on mass, and a quenching mass scale that evolves modestly upwards with redshift. This model further predicts a stellar mass-star formation rate relation that is in good agreement with observations to z~6. Our results suggest that this simple analytic framework captures the basic physical processes required to model the mean evolution of stars and metals in galaxies, despite not incorporating many canonical ingredients of galaxy formation models such as merging or disk formation.