Detailed cluster lensing profiles at large radii and the impact on cluster weak lensing studies
Detailed cluster lensing profiles at large radii and the impact on cluster weak lensing studies
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DOI：
10.1111/j.1365-2966.2011.18481.x
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发表时间：
2011-01
影响因子：
4.8
通讯作者：
M. Oguri;T. Hamana
中科院分区：
文献类型：
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作者：
M. Oguri;T. Hamana
在 N 体模拟中使用大量光线追踪，我们详细检查了巨大暗晕周围的透镜轮廓，特别强调维里半径周围的轮廓。我们将径向会聚剖面与我们简单的分析模型预测进行比较，径向会聚剖面是通过堆叠许多暗晕在光线追踪模拟中精确测量的。我们的分析模型由一个主晕组成，该主晕由具有三种不同截断形式的纳瓦罗-弗伦克-怀特 (NFW) 密度剖面建模，加上主晕周围的相关物质（双晕项）。我们发现平滑截断的 NFW 轮廓可以最好地再现模拟透镜轮廓，其范围超过维里半径的 10 倍。然后，我们使用该分析模型来研究簇弱透镜研究中的潜在偏差，其中在解释观察到的信号时通常假设单个未截断的 NFW 分量。我们发现，通过将减小的切向剪切剖面与 NFW 剖面拟合来推断的簇质量，如果拟合执行到 ∼10–30 arcmin，则往往会被低估 ∼5–10%。相比之下，对于相同的拟合范围，浓度参数通常被高估约 20%。我们还研究了计算弱透镜质量峰的信噪比时的偏差，发现显着质量峰的信噪比为 ≲4%。在附录中，我们提供了平滑截断的 NFW 配置文件的有用公式。
Using a large set of ray tracing in N-body simulations, we examine lensing profiles around massive dark haloes in detail, with a particular emphasis on the profile at around the virial radii. We compare radial convergence profiles, which are measured accurately in the ray-tracing simulations by stacking many dark haloes, with our simple analytic model predictions. Our analytic models consist of a main halo, which is modelled by the Navarro–Frenk–White (NFW) density profile with three different forms of the truncation, plus the correlated matter (two-halo term) around the main halo. We find that the smoothly truncated NFW profile best reproduces the simulated lensing profiles, out to more than 10 times the virial radius. We then use this analytic model to investigate potential biases in cluster weak lensing studies in which a single, untruncated NFW component is usually assumed in interpreting observed signals. We find that cluster masses, inferred by fitting reduced tangential shear profiles with the NFW profile, tend to be underestimated by ∼5–10 per cent if fitting is performed out to ∼10–30 arcmin. In contrast, the concentration parameter is overestimated typically by ∼20 per cent for the same fitting range. We also investigate biases in computing the signal-to-noise ratio of weak lensing mass peaks, finding them to be ≲4 per cent for significant mass peaks. In the appendices, we provide useful formulae for the smoothly truncated NFW profile.