James Webb telescope's largest-ever map of the universe unmasks hidden corners

Key Points:

• Astronomers have created the most detailed map yet of the cosmic web—the universe's largest structure—using data from the James Webb Space Telescope's (JWST) COSMOS-Web survey, which covers a sky area about the size of three full moons.
• The map reveals how galaxies have evolved over 13 billion years, showing that dense regions fostered rapid galaxy growth in the early universe but later became sites where star formation shut down.
• The study highlights that massive galaxies in dense environments tend to be quiescent due to mechanisms like dark matter halos heating gas and supermassive black holes quenching star formation, with these effects dominating up to about 7 billion years ago.
• In the more recent universe, environmental factors around galaxies increasingly suppress star formation by stripping material or preventing cold gas accumulation.
• The COSMOS-Web survey improves upon previous maps by providing better redshift precision and detecting more, fainter, and more distant galaxies, enabling astronomers to observe the cosmic web as it appeared when the universe was only a few hundred million years old; the catalog of 164,000 galaxies is publicly available.