JWST maps cosmic web nearly 14 billion years

On May 14, 2026, the COSMOS-Web team said data from NASA’s James Webb Space Telescope had produced the most detailed map yet of the cosmic web, the large-scale network of galaxy clusters, filaments and voids that shapes the universe. The work uses the COSMOS-Web survey, a 255-hour JWST treasury program built to combine wide sky coverage with the telescope’s infrared sensitivity. Researchers said the new reconstruction follows galaxy structure across 13.7 billion years of cosmic history, reaching back to when the universe was less than 1 billion years old. The paper was published in *The Astrophysical Journal*, with Hossein Hatamnia of the University of California, Riverside listed as lead author. ### How far back does this map actually go? The 13.7-billion-year figure refers to the span of cosmic history covered by the reconstruction, not to a single photograph taken at one instant. In the COSMOS-Web visualization, each galaxy is placed by distance and cosmic time, so the map shows nearby structure on one end and progressively earlier epochs farther out. Researchers said the outer edge reaches a time when the universe was less than 1 billion years old. (rit.edu) The paper says the team traced large-scale structure up to about redshift 7, a standard cosmology measure for very distant, very early galaxies. Hatamnia said in a university release that the survey lets scientists study galaxies in clusters and filamentary structures “all the way from when the universe was a billion years old up to the nearby universe.” (rit.edu) ### What is the “cosmic web” the researchers are mapping? The cosmic web is the large-scale framework in which galaxies are arranged, with dense filaments and clusters separated by lower-density voids. The COSMOS-Web team described it as a structure of dark matter and gas that underlies where galaxies and galaxy groups form and evolve. Bright yellow regions in the released slice mark denser concentrations of galaxies, while darker regions indicate relatively empty space, according to the team’s description. (iopscience.iop.org) The map is a reconstruction from galaxy positions in the survey field, rather than a direct image of dark matter itself. A separate COSMOS release in February described a high-resolution dark matter map of the same field made through gravitational lensing measurements. (rit.edu) ### Why could Webb do this when earlier surveys struggled? JWST’s infrared instruments can detect faint, distant galaxies that were harder to see with earlier observatories, especially at high redshift and through dust, the team said. COSMOS-Web was designed to use that sensitivity over a wider area than the deepest pencil-beam surveys, giving astronomers enough volume to follow structure instead of isolated objects. (rit.edu) COSMOS-Web covers a contiguous area of roughly 0.54 to 0.6 square degrees with NIRCam imaging in four filters, with additional MIRI coverage over a non-contiguous 0.2 square degrees, according to the project pages and overview material. The survey team says the program will contain about 1 million galaxies across cosmic time. ### What did the researchers say this map lets them study? (phys.org) Hossein Hatamnia said the survey was designed to provide the “wide, deep view” needed to see the cosmic web. Jeyhan Kartaltepe, a Rochester Institute of Technology professor and COSMOS co-leader, said one of the survey’s main goals was to use JWST’s sensitivity and resolution to trace the evolution of structure over the age of the universe. (cosmos.astro.caltech.edu) The paper abstract says the reconstruction is being used to study environmentally driven galaxy evolution up to about z~7. An RIT release said the new view shows how dense regions can enhance early mass assembly, while lower-mass systems see star formation increasingly suppressed at later times; that interpretation was attributed to the researchers describing the paper’s findings. (phys.org) ### Where does this fit in the broader COSMOS-Web project? COSMOS-Web is a subset of the larger COSMOS field, a long-running multiwavelength survey that spans data from X-ray to radio wavelengths and includes more than 2 million detected galaxies, according to the project site. The JWST component was set up as a Cycle 1 treasury program led by a large international team including Caitlin Casey and Jeyhan Kartaltepe. (iopscience.iop.org) In February 2026, the COSMOS collaboration also highlighted a dark matter map of the same field, built from gravitational lensing across a 0.54-square-degree region in the constellation Sextans. The public COSMOS-Web release site lists additional large-scale-structure density maps up to z=7 among its data products. On the next step, the paper is already published in *The Astrophysical Journal* and the COSMOS-Web collaboration says its survey products, including large-scale-structure maps, are publicly available through the project’s release pages for follow-on analysis by other researchers. (cosmos.astro.caltech.edu) (iopscience.iop.org)