Cluster strong lensing in the Millennium simulation: the effect of galaxies and structures along the line-of-sight
Cluster strong lensing in the Millennium simulation: the effect of galaxies and structures along the line-of-sight
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DOI：
10.1111/j.1365-2966.2009.15227.x
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发表时间：
2009-04
影响因子：
4.8
通讯作者：
E. Puchwein;S. Hilbert
中科院分区：
文献类型：
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作者：
E. Puchwein;S. Hilbert
我们使用射线跟踪通过千年模拟研究次级物质结构沿着的视线和星系中的恒星质量如何影响强大的集群透镜，特别是横截面的巨型弧。此外，我们还研究了星系团的爱因斯坦半径分布和巨弧的径向分布。我们发现，沿着视线的附加结构使强透镜光学深度增加了10%-25%，而单个星系团的强透镜横截面通常增加了10%-50%。团星系增加了强透镜光学深度的2倍，而interloping星系是不显着的。我们的结论是，这些影响需要考虑到巨大的弧丰度的预测，但他们是不够大，以充分考虑到预测和观测到的丰度之间的差异报告。此外，我们发现，爱因斯坦半径定义通过由临界曲线所包围的区域是10- 30%，大于那些定义通过径向表面质量密度分布。径向弧和切向弧对弧的径向分布的贡献可以清楚地区分。切向弧的径向分布是非常广泛的，并延伸到几个爱因斯坦半径。因此，单独的弧并不适合约束爱因斯坦半径。
We use ray-tracing through the Millennium simulation to study how secondary matter structures along the line-of-sight and the stellar mass in galaxies affect strong cluster lensing, in particular the cross-section for giant arcs. Furthermore, we investigate the distribution of the cluster Einstein radii and the radial distribution of giant arcs. We find that additional structures along the line-of-sight increase the strong-lensing optical depth by ∼10–25 per cent, while strong-lensing cross-sections of individual clusters are frequently boosted by as much as ∼50 per cent. The enhancement is mainly due to structures that are not correlated with the lens. Cluster galaxies increase the strong-lensing optical depth by up to a factor of 2, while interloping galaxies are not significant. We conclude that these effects need to be taken into account for predictions of the giant arc abundance, but they are not large enough to fully account for the reported discrepancy between predicted and observed abundances. Furthermore, we find that Einstein radii defined via the area enclosed by the critical curve are 10–30 per cent larger than those defined via radial surface mass density profiles. The contributions of radial and tangential arcs to the radial distribution of arcs can be clearly distinguished. The radial distribution of tangential arcs is very broad and extends out to several Einstein radii. Thus, individual arcs are not well suited for constraining Einstein radii.