We analyzed Chandra X-ray observations of five galaxy clusters whose atmospheric cooling times, entropy parameters, and cooling time to free-fall time ratios within the central galaxies lie below 1 Gyr, below 30 keV cm^2, and between 20 < tcool/tff < 50, respectively. These thermodynamic properties are commonly associated with molecular clouds, bright H-alpha emission, and star formation in central galaxies. However, none of these clusters have detectable H-alpha indicated in the ACCEPT database, nor do they have significant star formation rates or detectable molecular gas. Among these, only RBS0533 has a detectable radio/X-ray bubble which are commonly observed in cooling atmospheres. Signatures of uplifted, high metallicity atmospheric gas are absent. Despite its prominent X-ray bubble, RBS0533 lacks significant levels of molecular gas. Cold gas is absent at appreciable levels in these systems perhaps because their radio sources have failed to lift low entropy atmospheric gas to an altitude where the ratio of the cooling time to the free-fall time falls below unity.

中文翻译：

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隆起刺激的热不稳定冷却：扰流器集群

我们分析了五个星系团的钱德拉 X 射线观测，它们的大气冷却时间、熵参数和中央星系内冷却时间与自由落体时间的比率低于 1 Gyr、低于 30 keV cm^2 和 20 < tcool/ tff < 50，分别。这些热力学特性通常与分子云、明亮的 H-α 发射和中央星系的恒星形成有关。然而，这些星团都没有在 ACCEPT 数据库中显示出可检测到的 H-α，也没有显着的恒星形成率或可检测到的分子气体。其中，只有 RBS0533 具有可检测的无线电/X 射线气泡，这通常在冷却大气中观察到。没有抬升的高金属度大气气体的特征。尽管有突出的 X 射线气泡，但 RBS0533 缺乏显着水平的分子气体。