JWST maps 164,000 galaxies May 13

Hossein Hatamnia and an international team reported in a May 13 paper that data from NASA’s James Webb Space Telescope have been used to trace large-scale structure in the universe out to about redshift 7, using the COSMOS-Web survey. The work draws on the largest JWST survey so far, according to UC Riverside and the survey overview paper, and follows galaxies across about 13.7 billion years of cosmic history. (iopscience.iop.org) UC Riverside said the map links the galaxy distribution back to a time when the universe was about one billion years old. (news.ucr.edu) The study appeared in *The Astrophysical Journal*. The result is best understood not as a single photograph of 164,000 galaxies, but as a statistical map built from wide-area JWST imaging and distance estimates that place galaxies in three dimensions. (iopscience.iop.org) The underlying survey, COSMOS-Web, was designed to be both wide and deep enough to study early galaxies and their environments on large scales. Caitlin M. Casey and Jeyhan S. Kartaltepe led the 2023 overview of the program, which set out to discover thousands of galaxies in the epoch of reionization and connect galaxy growth to larger-scale structure. ### Where did the 164,000-galaxy figure come from? More than 164,000 galaxies were analyzed in the COSMOS-Web-based map, according to UC Riverside’s May 11 release and coverage of the new result. (iopscience.iop.org) The galaxies come from a contiguous patch of sky about the size of three full Moons, giving researchers enough area to trace filaments, dense nodes and voids rather than isolated objects. COSMOS-Web was built as a wide-field JWST program rather than a narrow deep pointing. The 2023 survey overview said the program was designed to provide large statistical samples across cosmic time, while a 2026 data-reduction paper described the project as wide-area JWST NIRCam imaging. (iopscience.iop.org) ### What exactly did the researchers publish on May 13? The May 13 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*. The author list is led by Hatamnia and includes Bahram Mobasher, Jeyhan S. Kartaltepe and Caitlin M. Casey, among others, spanning institutions in the United States, Europe, Asia and Chile. (news.ucr.edu) The paper focuses on large-scale structure — the network of filaments, sheets, clusters and voids often called the cosmic web. UC Riverside said the map is the most detailed yet produced from JWST data, while the paper’s title makes clear the analysis is aimed at tracing galaxy evolution within that structure up to redshift 7. (iopscience.iop.org) ### Why does a wide JWST survey matter here? JWST is often associated with very deep images of small patches of sky, but COSMOS-Web was designed to trade some depth for area. That matters because cosmic structure is not evenly distributed, and small fields can miss or overrepresent dense regions by chance. The survey overview said one goal was to map reionization and galaxy environments on scales large enough to reduce cosmic variance. (iopscience.iop.org) Hatamnia said in the UC Riverside release that COSMOS-Web was designed “from the start” to provide the wide, deep view needed to see the cosmic web. He said the data now let researchers study galaxy evolution in clusters and filaments from the early universe to the nearby universe. (news.ucr.edu) ### Is this a public resource or a one-off result? The COSMOS-Web effort is broader than a single science paper. The survey overview and the 2026 data-reduction paper show the collaboration has been publishing the observing strategy and the imaging pipeline alongside science analyses, creating a foundation for other teams to use the same field and catalogs. (arxiv.org) The next step is continued follow-up across the COSMOS-Web collaboration and the wider astronomy community. The May 13 analysis paper is already in *The Astrophysical Journal*, and the survey’s published overview and data-processing papers give other researchers named entry points — including Casey, Kartaltepe, Franco, Hatamnia and Mobasher — for additional studies using the same JWST field. (news.ucr.edu) (iopscience.iop.org 1) (iopscience.iop.org 2)