A team of international astronomers has observed for the first time how galaxies were formed in the early days of the universe in Chile, thanks to the ALMA telescope of the European Southern Observatory (ESO).
ALMA, the largest telescope array in the world, had been focusing on detecting the earliest galaxies emerging after the Big Bang, of which little was known until now.
According to ESO, the astronomers led by Roberto Maiolinio, from the University of Cambridge, changed their approach by not looking for the light from stars but focusing on the faint glow of ionized carbon, emitted from gas clouds within which stars form.
This allowed the astronomers to study the relation between newly created stars and the clumps that would go on to become the first galaxies.
"This is the most distant detection ever of this kind of emission from a normal galaxy, seen less than 1 billion years after the Big Bang. It gives us the opportunity to watch the build-up of the first galaxies," said Andrea Ferrara, co-author of an article about the discovery published in Monthly Notices of the Royal Astronomical Society.
"For the first time, we are seeing early galaxies not merely as tiny blobs, but as objects with internal structure," he added.
The astronomers focused on finding galaxies that were inconspicuous and out of the ordinary, which would go on to "reionize the universe" and eventually gave rise to most of the galaxies we see today.
In this search, ALMA obtained a thin but clear signal of glowing carbon from a galaxy named BDF3299 that could be a typical example of galaxies responsible for reionization of the universe.
However, the glow was not coming from the center of the galaxy, but from one of its sides.
According to the ESO team, this could be due to "central clouds being disrupted by the harsh environment created by the newly formed stars, both from their intense radiation and the effects of supernova explosions, while the carbon glow was tracing fresh cold gas being accreted from the intergalactic medium."