The Chromatic Point-spread Function of Weak Lensing Measurement in the Chinese Space Station Survey Telescope  

作　　者：Quanyu Liu Xinzhong Er Chengliang Wei Dezi Liu Guoliang Li Zuhui Fan Xiaobo Li Zhang Ban Dan Yue 

机构地区：[1]South-Western Institute for Astronomy Research,Yunnan University,Kunming 65000,China [2]Purple Mountain Observatory,Chinese Academy of Sciences,Nanjing 210023,China [3]Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China [4]College of Physics,Changchun University of Science and Technology,Changchun 130022,China

出　　处：《Research in Astronomy and Astrophysics》2023年第7期263-276,共14页天文和天体物理学研究（英文版）

基　　金：funded by the National Natural Science Foundation of China(NSFC)under Nos.11873006,11933002,11903082,and U1931210;the science research grants from the China Manned Space Project with Nos.CMS-CSST-2021-A01,CMS-CSST-2021A12,and CMS-CSST-2021-A07。

摘　　要：Weak gravitational lensing is a powerful tool in modern cosmology.To accurately measure the weak lensing signal,one has to control the systematic bias on a small level.One of the most difficult problems is how to correct the smearing effect of the Point-Spread Function(PSF)on the shape of the galaxies.The chromaticity of PSF for a broad-band observation can lead to new subtle effects.Since the PSF is wavelength-dependent and the spectrum energy distributions between stars and galaxies are different,the effective PSF measured from the star images will be different from those that smear the galaxies.Such a bias is called color bias.We estimate it in the optical bands of the Chinese Space Station Survey Telescope from simulated PSFs,and show the dependence on the color and redshift of the galaxies.Moreover,due to the spatial variation of spectra over the galaxy image,another higher-order bias exists:color gradient bias.Our results show that both color bias and color gradient bias are generally below 0.1%in CSST.Only for small-size galaxies,one needs to be careful about the color gradient bias in the weak lensing analysis using CSST data.

关 键 词：gravitational lensing:weak cosmology:observations astronomical instrumentation methods and techniques 

分 类 号：V447[航空宇航科学与技术—飞行器设计] P111[天文地球—天文学]