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arXiv 1002.1625astro-ph.CO
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第611章. II。X射线和强透镜分析

Abell 611. II. X-ray and strong lensing analyses

A. Donnarumma, S. Ettori, M. Meneghetti, R. Gavazzi, B. Fort, L. Moscardini, A. Romano, L. Fu, F. Giordano, M. Radovich, R. Maoli, R. Scaramella, J. Richard

摘要:

本文给出了对弛豫星系团Abell 611(z=0.288)的X射线发射和强透镜系统的分析结果。我们通过非参数方法推导出X射线质量估计,得到半径r ~ 700 kpc范围内星系团内介质的密度和温度分布;假设星系团处于流体静力平衡,采用物质密度分布,我们可以通过X射线数据恢复Abell 611的总质量分布。我们推导出的总投影质量在中心区域的阿贝尔611执行其强大的透镜功能的参数分析,通过公开可用的分析软件Lenstool。作为最后一步,我们比较了两种方法得到的结果。我们得到了一个很好的协议之间的X射线和强透镜总质量估计在中心区域(即半径r ~100 kpc),而边际分歧之间的两个质量估计外推的强透镜的结果在外部空间范围。我们认为,在这种情况下,X射线/强透镜质量的不一致可以解释的重子分量和暗物质的相对贡献的不正确的估计,所造成的强透镜分析中的不同质量分量之间的固有简并。我们讨论了一些可能的系统误差,影响质量估计的效果。我们发现X射线温度的测量值(以及因此的X射线总质量)对光谱分析中采用的背景有轻微的依赖性,M_200值的总偏差为1 σ统计误差的量级。强透镜质量的结果,而不是敏感的参数化的星系晕质量的中心区域,特别是建模的Brilliant星团星系(BCG)重子组件。

英文摘要:

We present the results of our analyses of the X-ray emission and of the strong lensing systems in the relaxed galaxy cluster Abell 611 (z=0.288). We infer the X-ray mass estimate deriving the density and temperature profiles of the intra-cluster medium within the radius r ~ 700 kpc through a non-parametric approach; assuming that the cluster is in hydrostatic equilibrium and adopting a matter density profile, we can recover the total mass distribution of Abell 611 via the X-ray data. We derive the total projected mass in the central region of Abell 611 performing a parametric analysis of its strong lensing features through the publicly available analysis software Lenstool. As a final step we compare the results obtained with both methods. We derive a good agreement between the X-ray and strong lensing total mass estimates in the central region (i.e. within the radius r ~100 kpc), while a marginal disagreement is found between the two mass estimates when extrapolating the strong lensing results in the outer spatial range. We suggest that in this case the X-ray/strong lensing mass disagreement can be explained by an incorrect estimate of the relative contributions of the baryonic component and of the dark matter, caused by the intrinsic degeneracy between the different mass components in the strong lensing analysis. We discuss the effect of some possible systematic errors that influence both mass estimates. We find a slight dependence of the measurements of the X-ray temperatures (and therefore of the X-ray total masses) on the background adopted in the spectral analysis, with total deviations on the value of M_200 of the order of the 1-sigma statistical error. The strong lensing mass results are instead sensitive to the parameterisation of the galactic halo mass in the central regions, in particular to the modelling of the Brightest Cluster Galaxy (BCG) baryonic component.

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