The early universe was a dark place. It was filled with hydrogen, which blocked out light, and nothing else. But when the first stars opened up and began illuminating their surroundings with UV radiation, light began to dominate. This happened in the era of reionization.

But before the universe became fully illuminated, a special, mysterious type of light pierced the darkness: Lyman-alpha radiation. Although the early universe was so dark that light could not pass through the opaque gas that dominated it, astronomers still detected some Lyman-alpha lines before the light shined in the epoch of reionization.

Where did it come from? This was an important unanswered question that many people were thinking about. Lyman-alpha radiation occurs in the UV range and originates from hydrogen atoms when their electrons move to a certain energy state. Lyman-alpha spectral lines are part of what astronomers call the Lyman-alpha forest.

The forest is a series of absorption lines resulting from hydrogen in distant astronomical objects. When their light passes through gas clouds at different redshifts, it creates a forest of Lyman-alpha lines.

“Explaining the surprising detection of Lyman alpha in these early galaxies is a major challenge for extragalactic studies,” write the authors of some of the new studies.

The study was published in the journal Nature Astronomy And we may have found the answer. Its title: “Deciphering Lyman-alpha radiation deep into the reionization era.” The lead author is Callum Whitten, a researcher at the Kavli Institute for Cosmology at the University of Cambridge in the United Kingdom.

“One of the most puzzling problems that arose in previous observations was detecting light from hydrogen atoms in the very early universe, which should have been completely blocked by the pure neutral gas formed after the Big Bang,” Whitten said in a press release. . release

“Many hypotheses have previously been put forward to explain the great escape of this ‘mysterious’ radiation.”

WST was created with the ability to peer into the early days of the universe. He was one of the main driving forces behind the entire effort. JWST’s ability to detect photons emitted by stars in protogalaxies in the early universe has opened a new window into the early universe and is leading us to answers to many long-standing questions. JWST has both the sensitivity and angular resolution to track ancient light back to its source.

This work shows that there was more galactic merging in the early universe than we can see before JWST started operating. These mergers and interactions, and the abundant star formation they give rise to, are responsible for both creating Lyman-alpha emissions and providing them with a pathway through the dense, opaque neutral hydrogen that dominated the young Universe.

In summary, the high rate of galaxy mergers in the young universe is responsible for the mysterious Lyman-alpha emission. The researchers are not done yet. They plan more detailed observations of galaxies in various stages of merger to further develop their ideas.