AGN heating and ICM cooling in the HIFLUGCS sample of galaxy clusters
AGN heating and ICM cooling in the HIFLUGCS sample of galaxy clusters
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DOI：
10.1051/0004-6361/200810836
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发表时间：
2008-10
影响因子：
6.5
通讯作者：
R. Mittal;D. Hudson;T. Reiprich;T. Clarke
中科院分区：
文献类型：
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作者：
R. Mittal;D. Hudson;T. Reiprich;T. Clarke
星系团中心的活动星系核（AGN）的气体冷却时间比哈勃时间短得多，它们已经成为足够强大的加热剂，以防止团内介质（ICM）的进一步冷却。我们对活动星系核加热-ICM冷却网络进行了深入的研究，将各种星系团参数与活动星系核中心的综合射电光度LR进行了比较，LR定义为10 MHz和15 G Hz之间的总同步加速器功率。这项研究是基于HIFLUGCS样本，包括64个X射线最亮的星系团。我们采用了中央冷却时间，tcool，作为诊断，以确定冷却性能的HIFLUGCS样品和分类集群与tcool 7.7 Gyr为非冷核心（NCC）集群。我们发现64个星系团中有48个（7.5%）包含与X射线峰值发射同空间或在50 h −1 71 kpc范围内的星系团中心射电源（CCRS）。此外，我们发现，发现一个CCRS的概率增加从45%到67%到100%的NCC，WCC和SCC集群，分别。我们总共使用了140个独立的无线电通量密度测量，其中超过54%的源在两个以上的频率下的数据延伸到500 MHz以下，从而能够确定LR的准确估计。我们发现，在SCC集群LR强烈依赖于集群规模，使更大的集群拥有更强大的无线电活动星系核。在SCC和部分WCC团簇中，LR和经典质量沉积速率之间观察到相同的趋势，并且可以量化为LR_（1.69±0.25）经典。我们还执行的亮度最亮的集群星系，LBCG，接近所有64个集群的LR和集群参数，如维里质量，M500，和热测量X射线光度，LX的X射线峰值的相关性。为此，我们使用2 MASS K波段的幅度和调用近红外球光度黑洞质量的关系转换LBCG超大质量黑洞质量，MBH。我们发现SCC集群的MBH和LR之间存在弱相关性，LR = 4.10±0.42 BH，尽管有一些异常值。我们发现LBCG与M500和LX对整个样品的良好的分离，SCC簇在两种情况下都显示出更紧密的趋势。我们讨论这些标度关系背后的冷却流和活动星系核反馈的背景下，似是而非的原因。我们的研究结果强烈建议在SCC集群，调节冷却的中心区域的活动星系核反馈机制。由于分散在这些相关性，这样的一个s之间的LR和stecMclassical或LR和MBH，增加从SCC到WCC集群，我们得出结论，必须有二次过程的工作，无论是与AGN加热或独立抵消WCC集群的辐射损失。
Active galactic nuclei (AGN) at the center of galaxy clusters with gas cooling times that are much shorter than the Hubble time have emerged as heating agents powerful enough to prevent further cooling of the intracluster medium (ICM). We carried out an intensive study of the AGN heating−ICM cooling network by comparing various cluster parameters to the integrated radio luminosity of the central AGN, LR, defined as the total synchrotron power between 10 MHz and 15 G Hz. This study is based on the HIFLUGCSsample comprising the 64 X-ray brightest galaxy clusters. We adopted the central cooling time, tcool, as the diagnostic to ascertain cooling properties of the HIFLUGCSsample and classify clusters with tcool 7.7 Gyr as non-cool-core (NCC) clusters. We find 48 out of 64 clusters (7 5%) contain cluster center radio sources (CCRS) cospatial with or within 50 h −1 71 kpc of the X-ray peak emission. Furthermore, we find that the p robability of finding a CCRS increases from 45% to 67% to 100% for NCC, WCC, and SCC clusters, respectively. We use a total of∼ 140 independent radio flux-density measurements, with data at more than two frequencies for more than 54% of the sources extending below 500 MHz, enabling the determination of accurate estimates of LR. We find that LR in SCC clusters depends strongly on the cluster scale such that more massive clusters harbor more powerful radio AGN. The same trend is observed between LR and the classical mass deposition rate, ˙ Mclassical in SCC and partly also in WCC clusters, and can be quantified as LR∝ ˙ M 1.69±0.25 classical . We also perform correlations of the luminosity for the brightest cluster galaxy, LBCG, close to the X-ray peak in all 64 clusters with LR and cluster parameters, such as the virial mass, M500, and the bolometric X-ray luminosity, LX. To this end, we use the 2MASS K-band magnitudes and invoke the near-infrared bulge luminosity-black hole mass relation to convert LBCG to supermassive black hole mass, MBH. We find a weak correlation between MBH and LR for SCC clusters, LR∼ M 4.10±0.42 BH , although with a few outliers. We find an excellent correlati on of LBCG with M500 and LX for the entire sample, the SCC clusters showing a tighter trend in both the cases. We discuss the plausible reasons behind these scaling relations in the context of cooling flows and AGN feedback. Our results strongly suggest an AGN-feedback machinery in SCC clusters, which regulates the cooling in the central regions. Since the dispersion in these correlations, such a s that between LR and ˙ Mclassical or LR and MBH, increases in going from SCC to WCC clusters, we conclude there must be secondary processes that work either in conjunction with the AGN heating or independently to counteract the radiative losses in WCC clusters.