COSMOS2025
COSMOS2025 is the definitive COSMOS-Web galaxy catalog — covering photometry, morphology, photometric redshifts, and physical parameters for over 700,000 galaxies from JWST, HST, and ground-based data. I led the production of this catalog.
What is COSMOS2025?
COSMOS2025 is the official data release of the COSMOS-Web survey — a 255-hour JWST program covering the COSMOS field, one of the most extensively observed extragalactic survey fields in the sky. The catalog provides a comprehensive multi-wavelength characterization of galaxies across cosmic time, from the local universe out to the epoch of reionization.
The catalog is available at cosmos2025.iap.fr, hosted at the Institut d’Astrophysique de Paris (IAP).
Key Facts
| Property | Value |
|---|---|
| Number of galaxies | > 700,000 |
| Survey area | ~0.54 deg² (NIRCam); ~0.2 deg² (MIRI) |
| JWST filters | F115W, F150W, F277W, F444W (NIRCam); F770W (MIRI) |
| Total photometric bands | 37 bands from 0.3 to 8 μm |
| Redshift precision | σ_MAD = 0.012 at m_F444W < 28 |
| Redshift range (photo-z) | 0 < z ≲ 9 |
| Stellar mass completeness | ~80% complete at log(M★/M☉) ~ 9 at z ~ 10 |
| Published in | Astronomy & Astrophysics, Vol. 704, A339 (2025) |
Data Products
The catalog combines JWST’s unprecedented near-infrared depth with an extensive multi-wavelength dataset:
Photometry is derived using two complementary techniques: fixed-aperture photometry on space-based bands, and profile-fitting photometry across all 37 bands spanning 0.3–8 μm. This dual approach maximises both precision and completeness.
Morphology is characterised for all detected sources using a combination of profile-fitting and machine-learning classification, enabling structural studies of galaxies from the local universe to cosmic dawn.
Photometric redshifts and physical parameters — including stellar masses, star formation rates, and non-parametric star formation histories — are derived from spectral energy distribution (SED) fitting. Redshift precision (σ_MAD = 0.012 at m_F444W < 28) represents a factor of ~2 improvement over COSMOS2020 at 26 AB mag.
Stellar mass completeness improves by 1 dex in stellar mass compared to COSMOS2020, reaching log(M★/M☉) ~ 7 at z ~ 0.2 and log(M★/M☉) ~ 9 at z ~ 10.
Why It Matters
COSMOS2025 represents a step-change in our ability to study galaxy formation and evolution across cosmic time. The combination of JWST’s infrared sensitivity with the COSMOS field’s extensive ancillary data enables:
- Studies of the earliest galaxies at the epoch of reionization (z > 6)
- Precise measurements of the galaxy stellar mass function across a wide redshift baseline
- Accurate characterisation of the galaxy–dark matter halo connection
- Constraints on quenching mechanisms and star formation histories
- A reference catalog for planning future spectroscopic follow-up (e.g. with MOONS, MSE, Roman)
Paper and Data Access
A&A, Vol. 704, A339 | doi:10.1051/0004-6361/202555799 | arXiv:2506.03243
Catalog downloads, documentation, interactive sky viewer, and data release notes.
My Role
I led the construction of the COSMOS2025 catalog, coordinating the photometric pipeline, SED fitting, and validation across the full 58-person collaboration. This involved:
- Designing and running the multi-band photometric extraction pipeline
- Coordinating photometric redshift and SED fitting across multiple codes
- Leading the validation against spectroscopic samples
- Producing all data products and documentation for the public data release
COSMOS2025 is the successor to COSMOS2020 and will serve as the reference catalog for the COSMOS community for years to come.
For more on my research using this catalog, see the Publications and halogal pages.