COSMOS-Web releases cosmic web map

The COSMOS-Web team said on May 14 that it had released what it called the most detailed map yet of the cosmic web, using observations from NASA’s James Webb Space Telescope. The new map reconstructs how galaxies trace the universe’s large-scale structure across 13.7 billion years of cosmic history, according to Rochester Institute of Technology and the University of California, Riverside. The work appears in *The Astrophysical Journal* and is led by Hossein Hatamnia, a graduate student at UC Riverside and Carnegie Observatories. The release adds a new cosmic-web reconstruction to the survey’s earlier public data products, which already included wide-field JWST images and galaxy catalogs. ### What exactly did the team release this week? RIT said on May 14 that the team released a three-dimensional map showing galaxies distributed through nearly 14 billion years, with dense filaments and clusters highlighted against large voids. UC Riverside said on May 11 that the reconstruction traces the network of galaxies back to when the universe was about 1 billion years old. (rit.edu) The paper is titled “Large-scale Structure in COSMOS-Web: Tracing Galaxy Evolution in the Cosmic Web up to z ∼ 7 with the Largest JWST Survey,” according to the journal and arXiv records. The study says the survey is the first wide-area, deep, near-infrared-selected program designed to study the cosmic web and the effect of environment on galaxy properties. ### How big is the survey behind the map? (rit.edu) COSMOS-Web is a 255-hour JWST Cycle 1 treasury program that maps a contiguous 0.6 square degree area with NIRCam imaging and a 0.2 square degree area with MIRI in parallel, according to the project site. The survey was designed to build a wide, deep view of the COSMOS field and is expected to contain about 1 million galaxies across cosmic time. (iopscience.iop.org) UC Riverside said the analysis behind the new cosmic-web map used 164,000 galaxies from the survey. The broader public data release from COSMOS-Web DR1 includes photometric redshifts and physical properties for about 780,000 galaxies, while a 2025 project note described the COSMOS2025 catalog as covering nearly 800,000 galaxies across 0.54 square degrees of sky. (cosmos.astro.caltech.edu) ### Who led the work and what did they say? Hossein Hatamnia was the lead author, while Jeyhan Kartaltepe of RIT was a co-author and a co-leader of the broader COSMOS survey, RIT said. The author list also includes Caitlin Casey and researchers from institutions in the United States, Europe, Asia and South America, according to the paper and university releases. (news.ucr.edu) Hatamnia said in UC Riverside’s release that “JWST has completely changed our view of the universe,” and that COSMOS-Web was designed to provide the wide, deep view needed to see the cosmic web. Kartaltepe said in RIT’s release that the data had enabled “an exquisite three-dimensional view” of the universe from a few million years after the Big Bang to today. (rit.edu) ### What does the map show besides galaxy positions? RIT said the team also released one of the most detailed high-resolution dark matter maps yet produced alongside the current paper and the initial COSMOS-Web data set. A COSMOS project update published on February 10 said researchers traced dark matter across a 0.54-square-degree region by measuring how unseen mass bends light from distant galaxies. (news.ucr.edu) The study’s abstract says the findings show large-scale structure shaping galaxy evolution, with dense regions linked to earlier mass assembly and later suppression of star formation in lower-mass systems. That interpretation comes from the paper’s authors and appears in the journal abstract and arXiv summary. ### Where can readers find the data and images now? (rit.edu) The COSMOS-Web DR1 site says the public release includes reduced NIRCam and MIRI mosaics, aperture and model-based photometric catalogs, photometric redshifts, physical properties and an interactive viewer. The viewer allows users to inspect the released images, overlay the catalog and spectroscopic redshift compilation, and examine source-by-source spectral energy distribution plots. (iopscience.iop.org) A project update posted on May 4 said the catalog had been updated to version 1.1 and that multi-band morphological measurements from GALFITM were available. The next step for outside researchers is straightforward: the images, catalog files and viewer are already live on the COSMOS-Web DR1 site maintained through the Institut d’Astrophysique de Paris. (cosmos2025.iap.fr)