According to new images from the James Webb Space Telescope (JWST), three galaxies that existed when the universe was a few hundred million years old have surrounded themselves with the gas that nurtured future stars.
The first to be observed around such young galaxies are gas plumes.
Three galaxies are so far away that we see them when the universe was 400 to 600 million years old.
They appear as little more than red blobs: their true nature is only revealed when observed with JWST’s infrared spectrometer, NIRSpec, which can pick up light absorbed or emitted by gas inside galaxies.
The spectrum shows that galaxies are surrounded by dense clouds of nearly pure hydrogen and helium, the earliest elements in the universe.
„The gas must be very widespread and cover a very large area of the galaxy,” said Darach Watson of the University of Copenhagen, Denmark, who participated in the study.
„This suggests that we see neutral hydrogen gas accreting into galaxies. That gas then cools, clumps and forms new stars.
„The fact that we see large gas reservoirs also indicates that the galaxies have not yet had time to form most of their stars.”
The galaxies are from what is known as the epoch of reionization.
Before this, the gas of the universe was mostly opaque; It was not until the light from the newly formed galaxies began to ionize the surrounding gas that it became transparent.
„We are moving away from isolated ecosystems of galaxies. At this point in the universe’s history, galaxies are all connected to the intergalactic medium with its filaments and primitive gas systems,” says Simon Nielsen from the university. Copenhagen also participated in the study.