ShapePipe: A new shape measurement pipeline and weak-lensing application to UNIONS/CFIS data
ShapePipe: A new shape measurement pipeline and weak-lensing application to UNIONS/CFIS data
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ShapePipe：一种新的形状测量管道和针对 UNIONS/CFIS 数据的弱透镜应用
DOI：
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发表时间：
2022
期刊：
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通讯作者：
A. McConnachie
中科院分区：
文献类型：
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作者：
A. Guinot;M. Kilbinger;S. Farrens;A. Peel;A. Pujol;M. Schmitz;J. Starck;T. Erben;R. Gavazzi;S. Gwyn;M. Hudson;Hendrik Hiledebrandt;T. Liaudat;L. Miller;I. Spitzer;L. Waerbeke;J. Cuillandre;S. Fabbro;A. McConnachie
联合航空公司是一项正在进行的合作，它将在四个光学波段中提供迄今最大的北方天空深度光度测量。作为这项合作的一部分，CFIS正在获取$r$波段数据，平均视距为0.65角秒，这是24.5级的完整数据，因此是弱透镜研究的理想选择。我们对覆盖天空1700度的CFIS$r$波段数据进行了第一次弱透镜分析。我们创建了一个星表，测量了4000万个星系的形状，对应于每平方角分钟6.8个星系的有效密度，并展示了低水平的系统性偏差。这项工作作为进一步的宇宙学研究的基础，当完成时，使用4800度的全联盟调查。在这里，我们介绍了一种新开发的弱透镜管道--ShapeTube。这条管道利用最先进的方法，如NgMix，精确测量星系形状。剪切定标是用准定标进行的。我们对点扩展函数(PSF)和星系形状进行了广泛的验证测试。此外，我们创建了逼真的图像模拟来验证估计的切变。我们量化了PSF模型的精度，并表明从PSF残差来衡量，系统学水平很低。与角尺度上的宇宙学贡献相比，它们对剪切两点关联函数的影响是次要的。图像模拟结果表明，相加剪切偏差小于5×10-4，剩余相乘剪切偏差最多为10-3美元。利用COSEBIS，我们发现在二阶剪切统计量中不存在显著的B模。我们给出了收敛图，并看到了E模与已知星团位置的明显关联。我们测量了普朗克星系团周围的堆积切向切变剖面，其值显著高于4西格玛。
UNIONS is an ongoing collaboration that will provide the largest deep photometric survey of the Northern sky in four optical bands to date. As part of this collaboration, CFIS is taking $r$-band data with an average seeing of 0.65 arcsec, which is complete to magnitude 24.5 and thus ideal for weak-lensing studies. We perform the first weak-lensing analysis of CFIS $r$-band data over an area spanning 1700 deg$^2$ of the sky. We create a catalogue with measured shapes for 40 million galaxies, corresponding to an effective density of 6.8 galaxies per square arcminute, and demonstrate a low level of systematic biases. This work serves as the basis for further cosmological studies using the full UNIONS survey of 4800 deg$^2$ when completed. Here we present ShapePipe, a newly developed weak-lensing pipeline. This pipeline makes use of state-of-the-art methods such as Ngmix for accurate galaxy shape measurement. Shear calibration is performed with metacalibration. We carry out extensive validation tests on the Point Spread Function (PSF), and on the galaxy shapes. In addition, we create realistic image simulations to validate the estimated shear. We quantify the PSF model accuracy and show that the level of systematics is low as measured by the PSF residuals. Their effect on the shear two-point correlation function is sub-dominant compared to the cosmological contribution on angular scales<100 arcmin. The additive shear bias is below 5x$10^{-4}$, and the residual multiplicative shear bias is at most $10^{-3}$ as measured on image simulations. Using COSEBIs we show that there are no significant B-modes present in second-order shear statistics. We present convergence maps and see clear correlations of the E-mode with known cluster positions. We measure the stacked tangential shear profile around Planck clusters at a significance higher than $4sigma$.