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The James Webb Space Telescope (JWST), launched in 2021, has already made significant strides in the field of astronomy, particularly through the efforts of the COSMOS-Web team. Consisting of nearly 50 researchers from various global institutions, the team was awarded over 200 hours of observation time—the most of any project during the telescope's first year. Unlike many studies that focus on narrower, deeper slices of the sky, COSMOS-Web opted for a broader approach. This decision has led to the discovery of ten times more galaxies than initially expected from early cosmic epochs.

"Revealing galaxies that were invisible at other wavelengths and seeing them appear on our computers was incredible and very gratifying," stated Maximilien Franco, a postdoctoral researcher of astrophysics at the University of Hertfordshire in the U.K.

The extensive view provided by the JWST enables astronomers not only to catalog distant galaxies but also to study how their characteristics, such as size, shape, and brightness, are influenced by their surroundings. These insights enhance our understanding of galaxy evolution. "This tells us a lot about what influenced these galaxies as they evolved," noted Rachel Kartaltepe, a member of the COSMOS-Web team.

Alongside their cataloging efforts, the team has published several scientific papers exploring the amassed data. One key study, recently posted to the preprint archive arXiv, investigates the brightest galaxies at the centers of galaxy groups, tracking their structure and star-forming activities over the last 12 billion years.

Another major objective of the COSMOS-Web project is to map structures from the Reionization Era, which occurred over 13 billion years ago when the first galaxies began to light up and clear the thick hydrogen fog that filled the early universe. To achieve this, researchers use early galaxies as markers to measure "reionization bubbles," vast regions where light from stars and galaxies created clearings in the primordial haze.

Additionally, the team has tested a machine learning technique to estimate the physical properties of galaxies within this extensive dataset. They also developed a new method to measure the brightness of distant galaxies more accurately. Unlike traditional techniques that sum light within a fixed area, this new method models the light's spread across a galaxy, allowing for more precise measurements and integration of JWST images with ground-based data without losing critical details.

The COSMOS-Web project continues to push the boundaries of our understanding of the universe, uncovering secrets from billions of years ago and providing new methodologies for future research.