English

Evaluating the Accuracy of Non-parametric Galaxy Morphological Indicator Measurements in the CSST Imaging Survey

Astrophysics of Galaxies 2025-06-11 v1

Abstract

The Chinese Space Station Telescope (CSST) is China's upcoming next-generation ultraviolet and optical survey telescope, with imaging resolution capabilities comparable to the Hubble Space Telescope (HST). In this study, we utilized a comprehensive sample of 3,679 CSST realistic mock galaxies constructed from HST CANDELS/GOODS-North deep imaging observations, with stellar masses log(M/M)>9.0\log\left(M_{*} / M_{\odot}\right) > 9.0 and redshifts z<2z < 2. We evaluate the detection capabilities of CSST surveys and the accuracy in measuring the non-parametric morphological indicators (CC, AA, GiniGini, M20M_{\rm 20}, AOA_{\rm O}, DOD_{\rm O}) of galaxies. Our findings show that in terms of galaxy detection capabilities, CSST's deep field surveys can achieve the same level as HST's deep field observations; however, in wide-field surveys, CSST exhibits a significant deficiency in detecting high-redshift, low-mass, low-surface-brightness galaxies. Regarding the measurement of galaxy morphology, CSST's deep field surveys achieve high accuracy across all indicators except for the asymmetry indicator (AA), whereas its wide-field surveys suffer from significant systematic biases. We thus provide simple correction functions to adjust the non-parametric morphological indicators obtained from CSST's wide-field and deep-field observations, thereby aligning CSST measurements with those from HST. This adjustment enables the direct application of non-parametric morphological classification methods originally developed for HST data to galaxies observed by CSST.

Keywords

Cite

@article{arxiv.2505.02127,
  title  = {Evaluating the Accuracy of Non-parametric Galaxy Morphological Indicator Measurements in the CSST Imaging Survey},
  author = {Yuchong Luo and Anhe Sha and Jian Ren and Xin Zhang and Xianmin Meng and Nan Li and F. S. Liu},
  journal= {arXiv preprint arXiv:2505.02127},
  year   = {2025}
}

Comments

15 pages, 14 figures, to be published in PASP. Comments welcome