HybPSF: Hybrid PSF reconstruction for the observed JWST NIRCam image

TL;DR

HybPSF is a hybrid PSF modeling method for JWST NIRCam data that combines simulations with observed residuals, significantly enhancing PSF accuracy for improved astronomical measurements.

Contribution

This paper introduces HybPSF, a novel hybrid PSF reconstruction technique that integrates WebbPSF simulations with observational residuals to improve PSF modeling accuracy.

Findings

HybPSF reduces PSF shape discrepancies by a factor of 10 for R^2.

HybPSF improves ellipticity precision by 50%.

The method enhances measurement reliability for JWST NIRCam data.

Abstract

The James Webb Space Telescope (JWST) ushers in a new era of astronomical observation and discovery, offering unprecedented precision in a variety of measurements such as photometry, astrometry, morphology, and shear measurement. Accurate point spread function (PSF) models are crucial for many of these measurements. In this paper, we introduce a hybrid PSF construction method called HybPSF for JWST NIRCam imaging data. HybPSF combines the WebbPSF software, which simulates the PSF for JWST, with observed data to produce more accurate and reliable PSF models. We apply this method to the SMACS J0723 imaging data and construct supplementary structures from residuals obtained by subtracting the WebbPSF PSF model from the data. Our results show that HybPSF significantly reduces discrepancies between the PSF model and the data compared to WebbPSF. Specifically, the PSF shape parameter ellipticity and size comparisons indicate that HybPSF improves precision by a factor of approximately 10 for \$R^2\$ and \$50\%\$ for \$e\$. This improvement has important implications for astronomical measurements using JWST NIRCam imaging data.