Automatic detection of gravitational arcs in wide-area survey data, comparison of the observed and the theoretically expected arc abundance

被星系团的引力透镜效应（即所谓的弧线）强烈扭曲的大量遥远星系，是在最高质量尺度上对非线性宇宙结构形成的潜在非常有力的测量。到目前为止，由于调查面积小，样本的统计不均匀性，在观测上知之甚少。为了改善这种情况，我们开发了快速“arcfinder”软件，用于自动检测大型图像中的弧线。arcfinder配备了有效的虚假检测过滤器，现在可以应用于现有和即将到来的广域调查数据，特别是CFHTLS-wide和Pan-STARRS PS 1调查。我们正在提议一个项目，其中arcfinder将应用于这些和可能的其他数据集。将进行校准运行，以确定电弧检测的效率和选择功能。现有的软件将用于模拟透镜的质量分布，产生检测到的弧线。同时，我们将改进弧丰度的理论预测，重点是理解所涉及的系统不确定性和样本方差的大小。正如许多研究表明的那样，我们希望这个项目能够大大提高对弧的丰度是否与标准宇宙学模型的预测相冲突的理解。

The abundance of distant galaxies which are strongly distorted by the gravitational lensing effect of galaxy clusters, so-called arcs, is a potentially very powerful measure for non-linear cosmological structure formation at the highest mass scales. Up to now, it is observationally poorly known because of the small area surveyed and statistical inhomogeneity of the sample. To improve this situation, we have developed the fast “arcfinder” software for the automatic detection of arcs in large images. Equipped with an efficient filter for spurious detections, the arcfinder is now ready to be applied to existing and upcoming wide-area survey data, in particular the CFHTLS-wide and the Pan-STARRS PS 1 surveys. We are proposing a project in which the arcfinder will be applied to these and possible other data sets. Calibration runs will be carried out to determine the efficiency and the selection function of the arc detections. Existing software will be used to model the mass distributions of the lenses producing the arcs detected. In parallel, we shall improve theoretical predictions of the arc abundance with an emphasis on understanding the systematic uncertainties involved and the magnitude of the sample variance. We expect this project to result in a substantially improved understanding of whether the abundance of arcs is in fact in conflict with the predictions of the standard cosmological model, as many studies suggest.