Overview
- The JWST COSMOS‑Web program assembled a 0.54‑square‑degree weak‑lensing mass map covering a sky area about 2.5 times the full Moon.
- Researchers measured subtle distortions in roughly 250,000 background galaxies, drawn from nearly 800,000 galaxies identified in about 255 hours of observations.
- The result is about twice as sharp as previous space‑based maps, resolving finer filaments and low‑mass halos that earlier surveys could not see.
- The mapping traces structures out to roughly 5 billion light‑years, capturing detail from the universe’s peak era of star formation.
- Initial comparisons align with ΛCDM expectations, and the field will serve as a high‑resolution benchmark for larger‑area surveys by ESA’s Euclid and NASA’s Nancy Grace Roman Space Telescope.