Validation of Fast Mocks Generation for CSST Photometric Survey

2025/06/16 by Hu Yiming, Yu Yu, Hu, Yiming +1
Engineering · #Calibration and Measurement Techniques #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Infrared Target Detection Methodologies #Satellite Image Processing and Photogrammetry

paper · pdf · doi:10.48550/arxiv.2506.13262

openalex publication_date 2025/06/16 · openalex created_date 2025/10/13 · openalex updated_date 2026/07/28

Abstract

Weak lensing has become a powerful tool for probing the matter distribution in the Universe and constraining cosmological parameters. This paper aims to explore the fast mock generation pipeline to obtain the covariance matrix of the 3× 2pt analysis for the upcoming China Space Station Telescope (CSST). We adopt the N_side pipeline, which generates matter distribution with lognormal assumptions, to create full-sky galaxy mocks with certain two-point statistics. We also employ the Markov-Chain Monte Carlo simulation to test the accuracy of the covariance matrix from the mock-generated galaxy catalogue. Our work validates the accuracy of the 3× 2pt statistics in both spherical harmonic space and real space. The critical scale below which the fractional error of correlation exceeds 1% can decrease as the resolution parameter N_side increases. After excluding certain scales, the covariance matrix from the mock-generated galaxy catalogue can constrain the cosmological parameters with 0.1% accuracy. This work demonstrates the potential of GLASS for real-space cosmological measurements and highlights the importance of discarding appropriate scales.

Citations

• Emission-line Stacking of 21cm Intensity Maps with MeerKLASS: Inference Pipeline and Application to the L-band Deep-field Data
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Related

• Mock Observations for the CSST Mission: Main Surveys -- the Mock Catalogue
• Exploring cosmological constraints of the weak gravitational lensing and galaxy clustering joint analysis in the CSST photometric survey
• Mock Observations for the CSST Mission: Main Surveys--An Overview of Framework and Simulation Suite
• CSST Strong Lensing Preparation: Cosmological Constraints Forecast from CSST Galaxy-Scale Strong Lensing
• Mitigation of nonlinear galaxy bias with a theoretical-error likelihood