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JWST Produces Most Detailed Dark-Matter Map to Date

The localized map sets a benchmark for upcoming Euclid or Roman surveys to place the result in wider context.

Overview

  • Deep JWST NIRCam imaging totaling 255 hours of the COSMOS field enabled weak-lensing analysis of roughly 800,000 background galaxies.
  • The reconstruction reaches about one-arcminute resolution, roughly twice as sharp as previous Hubble-based dark-matter maps.
  • Previously unresolved features emerge, including fine filaments, small halos, and bridges that trace the cosmic web.
  • The inferred mass distribution closely aligns with luminous matter, reinforcing expectations from the standard cosmological model.
  • Coverage spans only a small sky patch of roughly 2.5 full-moon areas, with broader mapping anticipated from ESA’s Euclid and NASA’s Nancy Grace Roman missions.