论文标题
从大型星系到星系簇的降水限制热光晕的限制
Constraints on precipitation-limited hot halos from massive galaxies to galaxy clusters
论文作者
论文摘要
我们对热弥漫性光环气体的简单分析模型提出了限制，该模型源自晕Halo质量的两个数量级（$ M_ {500} \ sim 10^{12.5} -10^{14.5} {14.5} m _ {\ odot} $）。该模型是由观察到的降水限制的流行率激励的，其主要游离参数是气体冷却时间尺度与自由下落时间尺度的中心比例（$ t _ {\ rm cool}/t _ {\ rm ff} $）。我们使用对大型星系，星系组和集群周围环境的集成X射线和热阳光s ZEL'Dovich观察，平均为Halo Mose Bins，并获得最合适的模型参数。我们发现$ t _ {\ rm cool}/t _ {\ rm ff} \ sim 50-110 $，具体取决于模型外推超出晕病毒半径，可能还取决于拟合分析中使用的数据集中存在的偏差。该模型充分描述了整个质量范围，除了中间质量晕圈（$ M_ {500} \ SIM 10^{13.5} M _ {\ odot} $），该M _ {\ odot} $）系统地略高于模型预测。但是，最适合$ t _ {\ rm cool}/t _ {\ rm ff} $的最佳拟合实际上超出了通常从单个系统的X射线观测得出的值（$ t _ {\ rm cool}/t _ {\ rm ff} \ rm ff} \ sim 10-30 $）。我们考虑了这些差异的几种解释，包括X射线选择偏见以及X射线光度和中央星系恒星质量之间的潜在抗相关性。
We present constraints on a simple analytical model for hot diffuse halo gas, derived from a fit spanning two orders of magnitude in halo mass ($M_{500} \sim 10^{12.5}-10^{14.5} M_{\odot}$). The model is motivated by the observed prevalence of a precipitation limit, and its main free parameter is the central ratio of gas cooling timescale to free-fall timescale ($t_{\rm cool}/t_{\rm ff}$). We use integrated X-ray and thermal Sunyaev-Zel'dovich observations of the environments around massive galaxies, galaxy groups and clusters, averaged in halo mass bins, and obtain the best-fitting model parameters. We find $t_{\rm cool}/t_{\rm ff} \sim 50-110$, depending on the model extrapolation beyond the halo virial radius and possibly on biases present in the data-sets used in the fitting analysis. The model adequately describes the entire mass range, except for intermediate mass halos ($M_{500} \sim 10^{13.5} M_{\odot}$) which systematically fall below the model predictions. However, the best fits for $t_{\rm cool}/t_{\rm ff}$ substantially exceed the values typically derived from X-ray observations of individual systems ($t_{\rm cool}/t_{\rm ff} \sim 10-30$). We consider several explanations for those discrepancies, including X-ray selection biases and a potential anti-correlation between X-ray luminosity and the central galaxy's stellar mass.
