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arXiv 2407.00370astro-ph.CO
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利用 Hyper Suprime-Cam 多波段图像实现精确剪切恢复

Accurate Shear Recovery with Multi-Band Images of Hyper Suprime-Cam

Cong Liu, Jun Zhang, Hekun Li, Pedro Alonso Vaquero, Wenting Wang

AI总结:

本文将 Fourier_Quad 方法应用于 HSC 多波段图像,证明五个光学波段的剪切星表均通过场畸变检验,且合并多波段剪切星表可使星系-星系透镜测量误差降低约 15%,表明多波段剪切测量能有效提升剪切统计精度。

摘要:

现有的大规模弱引力透镜巡天通常会为某一光学波段保留最佳视宁度条件,以最小化形状测量误差并最大化可用背景星系的数量。这是因为大多数常用的剪切测量方法对星系与 PSF(点扩散函数)尺寸比设置了显式或隐式阈值,低于该阈值时,其形状测量误差会急剧增大。利用 DECaLS 数据,我们此前已证明 Fourier_Quad 方法在普遍情况下对分辨率较差的星系图像表现非常好。因此,它是一个现成的工具,可用于多波段图像的剪切测量,而无需考虑各波段的视宁度条件。在本文中,我们将 Fourier_Quad 流程应用于 Hyper Suprime-Cam Subaru Strategic Program 第三次公开数据发布的多波段图像。我们表明,来自五个光学波段(g/r/i/z/y)的剪切星表均以非常高的精度通过了场畸变检验。利用 LOWZ 和 CMASS 星系作为前景透镜,我们表明,通过合并来自不同波段的剪切星表,星系-星系透镜测量中的误差棒可以减小约 15% 的因子。这表明,为了获得更好的剪切统计量,进行多波段剪切测量是值得的。

英文摘要:

The existing large scale weak lensing surveys typically reserve the best seeing conditions for a certain optical band to minimize shape measurement errors and maximize the number of usable background galaxies. This is because most popular shear measurement methods contain explicit or implicit thresholds on the galaxy-to-PSF (point spread function) size ratio, below which their shape measurement errors increase abruptly. Using the DECaLS data, we have previously demonstrated that the Fourier\_Quad method performs very well on poorly resolved galaxy images in general. It is therefore a ready tool for shear measurement with multi-band images regardless of their seeing conditions. In this paper, we apply the Fourier\_Quad pipeline on the multi-band images from the third public data release of the Hyper Suprime-Cam Subaru Strategic Program. We show that the shear catalogs from the five optical bands (g/r/i/z/y) all pass the field-distortion test with very high accuracy. Using the LOWZ and CMASS galaxies as foreground lenses, we show that the errorbar in the galaxy-galaxy lensing measurement can be decreased by factors around 15\% by combining shear catalogs from different bands. This indicates that it is worthful to do multi-bands shear measurements for a better shear statistics.

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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