The mass profile of A1413 observed with XMM-Newton: Implications for the M-T relation
The mass profile of A1413 observed with XMM-Newton: Implications for the M-T relation
复制标题
使用 XMM-Newton 观察到的 A1413 的质量分布：对 M-T 关系的影响
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
M. Arnaud
中科院分区：
文献类型：
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作者：
G. Pratt;M. Arnaud
我们介绍了XMM-Newton对z= 0:143的热（kT= 6:5 keV）星系团A1413的观测。我们在径向范围内构建了高达1700 kpc的气体和温度剖面。这个半径对应于相对于星团红移处的临界密度的密度对比度为500，或等于0:7r200。气相分布模式在外区得到了很好的描述，但在内250 kpc区更为集中。我们为内部区域引入了一个新的参数化，它允许更陡峭的气体密度分布。径向温度分布没有急剧下降，而是向外逐渐下降，在0:1r200和0:5r200之间下降了20%。预估温度分布可以用= 1:07 0:01的多向性模式很好地描述。我们发现，无论是投影效应还是PSF效应，都没有实质性地改变温度剖面的形式。假设流体静力平衡和球对称，我们使用观测到的温度分布和气体密度分布的新参数形式来计算星团的总质量分布。质量剖面与Moore等人（1999）的参数化非常吻合，这意味着一个非常集中的峰值物质分布。浓度参数在数值模拟的预期范围内。有几个迹象表明，超过密度对比600，气体可能不再处于流体静力平衡状态。在星团被激活部分的绝热数值模拟中有一个偏差，在这个意义上，星团温度的预测质量过高了40%。气体分布在中心达到峰值，主要是由于暗物质剖面的尖端。x射线气体与总质量比随着半径的增大而增大，达到f0:2。这些数据有力地支持了目前暗物质坍缩建模方法的有效性，但也证实了理解特定气体的物理特性是必不可少的。
We present an XMM-Newton observation of A1413, a hot (kT= 6:5 keV) galaxy cluster at z= 0:143. We construct gas and temperature profiles over the radial range up to1700 kpc. This radius corresponds to a density contrast 500 with respect to the critical density at the redshift of the cluster, or equivalently0:7r200. The gas distribution is well described by a model in the outer regions, but is more concentrated in the inner250 kpc. We introduce a new parameterisation for the inner regions, which allows a steeper gas density distribution. The radial temperature profile does not exhibit a sharp drop, but rather declines gradually towards the outer regions, by20% between 0:1r200 and 0:5r200. The projected temperature profile is well described by a polytropic model with= 1:07 0:01. We find that neither projection nor PSF eects change substantially the form of the temperature profile. Assuming hydrostatic equilibrium and spherical symmetry, we use the observed temperature profile and the new parametric form for the gas density profile to produce the total mass distribution of the cluster. The mass profile is remarkably well fitted with the Moore et al. (1999) parameterisation, implying a very centrally peaked matter dis- tribution. The concentration parameter is in the range expected from numerical simulations. There are several indications that beyond a density contrast 600, the gas may no longer be in hydrostatic equilibrium. There is an oset with respect to adia- batic numerical simulations in the virialised part of the cluster, in the sense that the predicted mass for the cluster temperature is40% too high. The gas distribution is peaked in the centre primarily as a result of the cusp in the dark matter profile. The X-ray gas to total mass ratio rises with increasing radius to fgas 0:2. These data strongly support the validity of the current approach for the modeling of the dark matter collapse, but confirm that understanding the gas specific physics is essential.