We present the data reduction methodology used for the COSMOS-Web survey JWST NIRCam data. Covering 0.54 deg^2 with four broadband filters (F115W, F150W, F277W, F444W) and a total exposure time of approximately 270 hours, COSMOS-Web represents the largest contiguous field surveyed during JWST Cycle 1, posing unique data reduction challenges due to its extensive scale. By combining the official JWST Calibration Pipeline with custom improvements for noise removal, background subtraction, and astrometric alignment, we achieve high fidelity science-ready mosaics. We detail the systematic approach employed in the three stages of the JWST Calibration Pipeline. The data, collected in three epochs from January 2023 to January 2024, encompass 152 visits and have been processed into 20 mosaic tiles to optimize computational efficiency and data processing. The final data products achieve 5 sigma depths of 26.7-28.3 AB mag in 0.15" apertures. The processed and calibrated datasets are made available to the public.
@article{arxiv.2506.03256,
title = {COSMOS-Web: Comprehensive Data Reduction for Wide-Area JWST NIRCam Imaging},
author = {Maximilien Franco and Caitlin M. Casey and Anton M. Koekemoer and Daizhong Liu and Micaela B. Bagley and Henry Joy McCracken and Jeyhan S. Kartaltepe and Hollis B. Akins and Olivier Ilbert and Marko Shuntov and Santosh Harish and Brant E. Robertson and Rafael C. Arango-Toro and Andrew J. Battisti and Nima Chartab and Nicole E. Drakos and Andreas L. Faisst and Carter Flayhart and Ghassem Gozaliasl and Michaela Hirschmann and Richard Massey and Jason Rhodes and Zahra Sattari and Diana Scognamiglio and John R. Weaver and Lilan Yang and Jorge A. Zavala and Edward M. Berman and Fabrizio Gentile and Steven Gillman and Arianna S. Long and Georgios Magdis and Jacqueline E. McCleary and Jed McKinney and Bahram Mobasher and Louise Paquereau and Armin Rest and David B. Sanders and Sune Toft and Si-Yue Yu},
journal= {arXiv preprint arXiv:2506.03256},
year = {2025}
}