June 18, 2025

Last week, we released the COSMOS2025 galaxy catalog from the COSMOS-Web survey, offering photometric and physical measurements for nearly 800,000 galaxies across 0.54 square degrees of sky — roughly the area covered by three full moons. This represents the largest and deepest survey of its kind to date and opens the door to a wealth of new discoveries about our Universe.
 

To build this catalog, we combined an unprecedented 37 multiwavelength images from major ground- and space-based observatories, leveraging the rich legacy of observations in the COSMOS field. This ambitious effort required the development of innovative techniques to simultaneously extract photometry and morphology for every galaxy across all bands. The result is a highly uniform dataset that delivers some of the most accurate redshifts and galaxy properties currently available — made possible through the efforts of a dedicated and collaborative team.

COSMOS2025 is already enabling exciting science: early results include the discovery of exceptionally bright and massive galaxies from within the first 500 million years after the Big Bang, and groundbreaking studies of stellar mass assembly, star formation, and galaxy clustering across 96% of cosmic history. These early highlights showcase the transformative power of COSMOS-Web and the COSMOS2025 catalog in reshaping our understanding of how galaxies, and the Universe, evolve.

Demonstration of the performance of our cataloging methodology with SourceXtractor++ over a relatively crowded and randomly selected 20′′ × 20′′ area. The top/middle/bottom rows show the science/model/residual images in five wide filters: HSC g, HST/ACS F814W, UltraVISTA KS , NIRCam F277W and MIRI F770W.