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arXiv 1603.03035astro-ph.COastro-ph.GA
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Sunyaev-Zel'dovich选择星系团0 < z < 1.5时团内介质金属丰度的演化

The Evolution of the Intracluster Medium Metallicity in Sunyaev-Zel'dovich-Selected Galaxy Clusters at 0 < z < 1.5

M. McDonald, E. Bulbul, T. de Haan, E. D. Miller, B. A. Benson, L. E. Bleem, M. Brodwin, J. E. Carlstrom, I. Chiu, W. R. Forman, J. Hlavacek-Larrondo, G. P. Gar… 展开作者

M. McDonald, E. Bulbul, T. de Haan, E. D. Miller, B. A. Benson, L. E. Bleem, M. Brodwin, J. E. Carlstrom, I. Chiu, W. R. Forman, J. Hlavacek-Larrondo, G. P. Garmire, N. Gupta, J. J. Mohr, C. L. Reichardt, A. Saro, B. Stalder, A. A. Stark, J. D. Vieira

摘要:

本文给出了用钱德拉、XMM-牛顿和朱雀空间望远镜观测到的153个星系团的X射线光谱分析结果。这些星系团的跨度为0 < z < 1.5,是从2500平方度的南极望远镜Sunyaev Zel'dovich(SPT-SZ)巡天中发现的一个更大的、经过质量选择的星系团样本中抽取的。与总的组合曝光时间为9.1毫秒,这些数据产生最强的约束,迄今为止的演化的金属含量的簇内介质(ICM)。我们没有发现全球(r&lt;R500)ICM金属丰度(dZ/dz = -0.06 +/- 0.04 Zsun)强烈演化的证据,z=0.6时的平均值为<Z>= 0.23 +/- 0.01 Zsun,分散度为0.08 +/- 0.01 Zsun。这些结果意味着ICM中超过60%的金属在z=1时已经就位(95%置信度),与早期(z&gt;1)富集的情况一致。我们发现,在协议与以前的工作,一个显着更高的平均值的金属丰度中心的冷核心集群与非冷核心集群。我们发现了冷核星系团中心金属丰度演化的微弱证据(dZ/dz = -0.21 +/-0.11 Zsun),这足以解释过去~10 Gyr中心金属丰度的增强。我们没有发现核外金属丰度演化的证据(dZ/dz = -0.03 +/-0.06 Zsun),冷核和非冷核簇之间的核切除金属丰度没有显著差异。这表明在r&gt;0.15R500时,强射电型活动星系核反馈并不显著改变金属的分布。考虑到当前一代X射线望远镜在限制ICM金属丰度z&gt;1方面的局限性,这项工作的重大改进可能需要下一代X射线任务。

英文摘要:

We present the results of an X-ray spectral analysis of 153 galaxy clusters observed with the Chandra, XMM-Newton, and Suzaku space telescopes. These clusters, which span 0 < z < 1.5, were drawn from a larger, mass-selected sample of galaxy clusters discovered in the 2500 square degree South Pole Telescope Sunyaev Zel'dovich (SPT-SZ) survey. With a total combined exposure time of 9.1 Ms, these data yield the strongest constraints to date on the evolution of the metal content of the intracluster medium (ICM). We find no evidence for strong evolution in the global (r<R500) ICM metallicity (dZ/dz = -0.06 +/- 0.04 Zsun), with a mean value at z=0.6 of <Z> = 0.23 +/- 0.01 Zsun and a scatter of 0.08 +/- 0.01 Zsun. These results imply that >60% of the metals in the ICM were already in place at z=1 (at 95% confidence), consistent with the picture of an early (z>1) enrichment. We find, in agreement with previous works, a significantly higher mean value for the metallicity in the centers of cool core clusters versus non-cool core clusters. We find weak evidence for evolution in the central metallicity of cool core clusters (dZ/dz = -0.21 +/- 0.11 Zsun), which is sufficient to account for this enhanced central metallicity over the past ~10 Gyr. We find no evidence for metallicity evolution outside of the core (dZ/dz = -0.03 +/- 0.06 Zsun), and no significant difference in the core-excised metallicity between cool core and non-cool core clusters. This suggests that strong radio-mode AGN feedback does not significantly alter the distribution of metals at r>0.15R500. Given the limitations of current-generation X-ray telescopes in constraining the ICM metallicity at z>1, significant improvements on this work will likely require next-generation X-ray missions.

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