Are group- and cluster-scale dark matter haloes overconcentrated?
Are group- and cluster-scale dark matter haloes overconcentrated?
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DOI：
10.1093/mnras/stt1585
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发表时间：
2013-08
影响因子：
4.8
通讯作者：
M. Auger;J. M. Budzynski;V. Belokurov;Sergey E. Koposov;I. McCarthy
中科院分区：
文献类型：
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作者：
M. Auger;J. M. Budzynski;V. Belokurov;Sergey E. Koposov;I. McCarthy
我们调查的晕质量，M_200，和浓度，c之间的关系，为26组和集群规模的强引力透镜的样本。与以前的结果相比，我们发现这些系统只是~ 0.1德克斯超过集中比类似质量的暗物质模拟晕; M_200 = 10^14 M_sun的晕的浓度为log c = 0.78\pm0.05，而在类似红移（z ~ 0.4）下对具有该质量的晕的模拟预测log c ~ 0.56 - 0.71。我们还发现，尽管我们的样本量很大，但我们无法对M_200-c关系的斜率做出信息性推断;我们注意到，在以前的研究中发现的陡峭斜率往往遵循M_200和c之间的协方差的斜率，这表明这些结果可能测量的是数据中的分散性，而不是内在信号。此外，我们的结论是，我们无法约束的M_200-c斜率是由于晕质量的范围有限，明确地模拟我们的晕质量分布，我们认为，其他研究可能会产生偏见的结果，通过使用不正确的分布晕质量。
We investigate the relationship between the halo mass, M_200, and concentration, c, for a sample of 26 group- and cluster-scale strong gravitational lenses. In contrast with previous results, we find that these systems are only ~ 0.1 dex more over-concentrated than similar-mass halos from dark matter simulations; the concentration of a halo with M_200 = 10^14 M_sun is log c = 0.78\pm0.05, while simulations of halos with this mass at similar redshifts (z ~ 0.4) predict log c ~ 0.56 - 0.71. We also find that we are unable to make informative inference on the slope of the M_200-c relation in spite of our large sample size; we note that the steep slopes found in previous studies tend to follow the slope in the covariance between M_200 and c, indicating that these results may be measuring the scatter in the data rather than the intrinsic signal. Furthermore, we conclude that our inability to constrain the M_200-c slope is due to a limited range of halo masses, as determined by explicitly modelling our halo mass distribution, and we suggest that other studies may be producing biased results by using an incorrect distribution for their halo masses.