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arXiv 0910.4013astro-ph.CO
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源性质对富星系团强透镜效应的影响

Impacts of Source Properties on Strong Lensing by Rich Galaxy Clusters

G. J. Gao, Y. P. Jing, S. Mao, G. L. Li, X. Kong

摘要:

我们使用一个高分辨率的$N$体模拟来研究背景星系的性质,包括红移,大小,形状和集群的影响,对形成巨弧的效率,通过引力透镜的丰富的星系团。对10个大质量星系团在两个红移(即$z_{\rm l} \sim 0.2$和0.3)上进行了两大组光线追迹模拟。在$z\sim0.2$下模拟晶状体簇的维里质量($M_{\rm vir}$)范围为$6.8\times10^{14} h^{-1} {M_{\odot}}$至$1.1\times 10^{15} h^{-1} M_{\odot}$。利用宇宙演化巡天(COSMOS)的成像数据,获得了$I$波段亮度大于25等的背景星系信息。围绕$1.7\times 10^5$强透镜实现与这些图像作为背景星系已被执行的每一组。我们发现,形成巨大的弧$z_{\rm l}=0.2$集群的效率是大致一致的观测。富星系团产生巨弧的效率与源的大小和星系团的聚集程度关系不大。我们的主要发现是,一小部分($\sim 1/3$)具有细长形状(例如椭圆率$ε=1-b/a>0.5$)的星系可以大幅增加巨弧的数量。与最近的研究相比,其中一个均匀的椭圆率分布从0到0.5是用于源,通过直接观察到的形状分布增加了一个因素$\sim2$的巨弧的数量。我们的结果表明,它是必要的帐户的源信息和调查参数(如点扩散函数,视宁度)作出正确的预测巨弧,并进一步约束宇宙学参数。(节略)

英文摘要:

We use a high-resolution $N$-body simulation to investigate the influence of background galaxy properties, including redshift, size, shape and clustering, on the efficiency of forming giant arcs by gravitational lensing of rich galaxy clusters. Two large sets of ray-tracing simulations are carried out for 10 massive clusters at two redshifts, i.e. $z_{\rm l} \sim 0.2$ and 0.3. The virial mass ($M_{\rm vir}$) of the simulated lens clusters at $z\sim0.2$ ranges from $6.8\times10^{14} h^{-1} {M_{\odot}}$ to $1.1\times 10^{15} h^{-1} M_{\odot}$. The information of background galaxies brighter than 25 magnitude in the $I$-band is taken from Cosmological Evolution Survey (COSMOS) imaging data. Around $1.7\times 10^5$ strong lensing realizations with these images as background galaxies have been performed for each set. We find that the efficiency for forming giant arcs for $z_{\rm l}=0.2$ clusters is broadly consistent with observations. The efficiency of producing giant arcs by rich clusters is weakly dependent on the source size and clustering. Our principal finding is that a small proportion ($\sim 1/3$) of galaxies with elongated shapes (e.g. ellipticity $ε=1-b/a>0.5$) can boost the number of giant arcs substantially. Compared with recent studies where a uniform ellipticity distribution from 0 to 0.5 is used for the sources, the adoption of directly observed shape distribution increases the number of giant arcs by a factor of $\sim2$. Our results indicate that it is necessary to account for source information and survey parameters (such as point-spread-function, seeing) to make correct predictions of giant arcs and further to constrain the cosmological parameters.(abridged)

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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