Iron Abundance in the Intracluster Medium at High Redshift
Iron Abundance in the Intracluster Medium at High Redshift
复制标题
高红移下簇内介质中的铁丰度
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
C. Norman
中科院分区：
文献类型：
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作者：
P. Tozzi;P. Rosati;S. Ettori;S. Borgani;V. Mainieri;C. Norman
我们对18个红移0.3 < z < 1.3的遥远星系团的x射线光谱进行了分析。其中大多数是用钱德拉卫星在36至180公里的长时间曝光下观测到的。对于其中两个z bbb101星团，我们也使用了xmm -牛顿的深度观测。总的来说，这些团簇探测的温度范围为3 keV ~ kT ~ 8 keV。我们的分析旨在推导出星系团内介质（ICM）中的铁丰度到迄今为止探测到的最高红移。利用不同红移区簇子样本的组合光谱拟合，我们研究了平均ICM金属丰度随宇宙时代的演变。我们发现在= 0.8处的平均铁丰度为Z = 0.25 Z☉，与局部典型金属丰度值Z≃0.3 Z☉在1 σ置信水平（c.l.）内一致。中低温团簇（kT < 5 keV）往往比高温团簇具有更大的铁丰度。在红移~ 1.2（四个星团在z >.1处），我们获得了统计上显著的铁K线检测，只有一个星团（z > 0.10 z☉在90% c.l.）。结合目前钱德拉和XMM在z→1处的所有数据集，测量到的平均金属丰度为= 0.21 z☉（1 σ误差），因此表明平均铁丰度在z→1.2处没有演变。
We present the analysis of the X-ray spectra of 18 distant clusters of galaxies with redshift 0.3 < z < 1.3. Most of them were observed with the Chandra satellite in long exposures ranging from 36 to 180 ks. For two of the z > 1 clusters, we also use deep XMM-Newton observations. Overall, these clusters probe the temperature range 3 keV ≲ kT ≲ 8 keV. Our analysis is aimed at deriving the iron abundance in the intracluster medium (ICM) out to the highest redshifts probed to date. Using a combined spectral fit of cluster subsamples in different redshift bins, we investigate the evolution of the mean ICM metallicity with cosmic epoch. We find that the mean Fe abundance at = 0.8 is Z = 0.25 Z☉, consistent with the local canonical metallicity value, Z ≃ 0.3 Z☉, within the 1 σ confidence level (c.l.). Medium- and low-temperature clusters (kT < 5 keV) tend to have larger iron abundances than hot clusters. At redshift ~ 1.2 (four clusters at z > 1), we obtain a statistically significant detection of the Fe K line in only one cluster (Z > 0.10 Z☉ at the 90% c.l.). Combining all the current data sets from Chandra and XMM at z > 1, the average metallicity is measured to be = 0.21 Z☉ (1 σ error), thus suggesting no evolution of the mean iron abundance out to z ≃ 1.2.