Impact of point spread function higher moments error on weak gravitational lensing II: A comprehensive study

• Published in: Monthly notices of the Royal Astronomical Society
• Main Authors: Zhang, Tianqing, Almoubayyed, Husni, Mandelbaum, Rachel, Meyers, Joshua E., Jarvis, Mike, Kannawadi, Arun, Schmitz, Morgan A., Guinot, Axel
• Format: Journal Article
• Language: English
• Published: United States Royal Astronomical Society 21.11.2022
• Subjects: ASTRONOMY AND ASTROPHYSICS; gravitational lensing: weak; methods: data analysis
• ISSN: 0035-8711; 1365-2966

Weak lensing is one of the most powerful probes for dark matter and dark energy science, although it faces increasing challenges in controlling systematic uncertainties as the statistical errors become smaller. The Point Spread Function (PSF) needs to be precisely modeled to avoid systematic error on the weak lensing measurements. The weak lensing biases induced by errors in the PSF model second moments, i.e. its size and shape, are well-studied. However, Zhang et al. (2021) showed that errors in the higher moments of the PSF may also be a significant source of systematics for upcoming weak lensing surveys. Therefore, this work comprehensively investigate the modeling quality of PSF moments from the 3rd to 6th order, and propagate the PSFEX higher moments modeling error in the HSC survey dataset to the weak lensing shear-shear correlation functions and their cosmological analyses. The overall multiplicative shear bias associated with errors in PSF higher moments can cause a ~0.1σ shift on the cosmological parameters for LSST Y10, while the associated additive biases can induce 1σ uncertainties in cosmology parameter inference for LSST Y10, if not accounted. Here, we compare the PSFEX model with PSF in Full FOV (PIFF), and find similar performance in modeling the PSF higher moments. We conclude that PSF higher moment errors of the future PSF models should be reduced from those in current methods, otherwise needed to be explicitly modeled in the weak lensing analysis.