FRANCE: Astronomers have discovered a giant protogalaxy 10 billion light years away, and found that it is about four times larger in diameter than our Milky Way.
Astronomers led by the California Institute of Technology discovered the galaxy-in-the-making that is actively being fed cool primordial gas tracing back to the Big Bang.
Using the Caltech-designed and – built Cosmic Web Imager (CWI) at Palomar Observatory, researchers imaged the protogalaxy and found that it is connected to a filament of intergalactic medium, the cosmic web made of diffuse gas that crisscrosses between galaxies and extends throughout the universe.
The finding provides the strongest observational support yet for what is known as the cold-flow model of galaxy formation. That model holds that in the early universe, relatively cool gas funneled down from the cosmic web directly into galaxies, fueling rapid star formation.
“This is the first smoking-gun evidence for how galaxies form,” said Christopher Martin, professor of physics at Caltech, principal investigator on CWI, and lead author of the new paper to be published in the journal Nature.
“Even as simulations and theoretical work have increasingly stressed the importance of cold flows, observational evidence of their role in galaxy formation has been lacking,” Martin said.
The protogalactic disk the team has identified is about 400,000 light years across – about four times larger in diameter than our Milky Way.
