Cosmological Simulations of the Preheating Scenario for Galaxy Cluster Formation: Comparison to Analytic Models and Observations
Cosmological Simulations of the Preheating Scenario for Galaxy Cluster Formation: Comparison to Analytic Models and Observations
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星系团形成预热场景的宇宙学模拟：与分析模型和观测结果的比较
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发表时间：
2007
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影响因子：
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通讯作者：
G. Bryan
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文献类型：
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作者：
J. Younger;G. Bryan
我们进行了一组非辐射宇宙学模拟的预热intraclustermedium中的气体的熵均匀地提高在高红移。这些模拟的结果首先用于测试当前在平滑吸积极限中通过熵输入进行预热的分析技术。当未修改的配置文件是直接从模拟，我们发现，这个模型是在很好的协议与我们的模拟结果。这表明，预热有效地平滑吸积气体，因此，在未修改的配置文件的转变是一个很好的近似，即使与现实的吸积历史。当我们仔细检查模拟结果时，我们没有发现熵放大的有力证据，至少对于这里采用的高红移预热模型。在本文的第二部分中，我们将预热模拟的结果与最近的观测结果进行了比较。我们表明，在与以前的工作一致，对于一个合理的预热量，可以找到一个令人满意的匹配的质量-温度和亮度-温度的关系。然而，正如以前的作者所指出的，我们发现模拟组的熵分布与观测结果相比过于平坦。特别是，虽然丰富的集群收敛在大半径的绝热自相似标度，没有一个值的熵输入预热过程中可以同时再现核心和外部熵水平。因此，我们确认，简单的预热方案星系团的形成，其中熵普遍注入高红移，是不一致的观测。
We perform a set of nonradiative cosmological simulations of a preheated intracluster medium in which the entropy of the gas was uniformly boosted at high redshift. The results of these simulations are used first to test the current analytic techniques of preheating via entropy input in the smooth accretion limit. When the unmodified profile is taken directly from simulations, we find that this model is in excellent agreement with the results of our simulations. This suggests that preheated efficiently smooths the accreted gas, and therefore a shift in the unmodified profile is a good approximation even with a realistic accretion history. When we examine the simulation results in detail, we do not find strong evidence for entropy amplification, at least for the high-redshift preheating model adopted here. In the second section of the paper, we compare the results of the preheating simulations to recent observations. We show—in agreement with previous work—that for a reasonable amount of preheating, a satisfactory match can be found to the mass-temperature and luminosity-temperature relations. However, as noted by previous authors, we find that the entropy profiles of the simulated groups are much too flat compared to observations. In particular, while rich clusters converge on the adiabatic self-similar scaling at large radius, no single value of the entropy input during preheating can simultaneously reproduce both the core and outer entropy levels. As a result, we confirm that the simple preheating scenario for galaxy cluster formation, in which entropy is injected universally at high redshift, is inconsistent with observations.