When galaxies begin to “die,” they cease to form stars. Through the Atacama Large Millimeter / submillimeter Array (ALMA) telescope, a group of astronomers managed to capture the beginning of this process for the first time about 9 million light years.
According to the study published in the scientific journal Nature Astronomy, the scientists observed that the ID2299 galaxy was undergoing an extreme transformation process, expelling almost half of all its gas, which is used in the formation of stars.
The discovery was made by chance when the team responsible for the study was analyzing 100 distant galaxies through ALMA to study the properties of its gases. ID2299 was observed by the telescope for just a few minutes, but it was long enough for researchers to detect the phenomenon and collect data.
The scientists detail that the process is occurring at a surprising rate, equivalent to 10,000 suns a year and, behind the phenomenon in question, there may be a collision with another galaxy.
One of the “clues” that alerted astronomers to what was happening was the presence of a “tidal tail”: an elongated stream of stars and gas that extends into interstellar space and that arises when there is a merger between two galaxies . Normally, “tidal tails” are too faint to be seen in galaxies so far away, however, astronomers were able to do so at the time it was being launched into space.
It is believed that the winds caused by star formation and the activity of black holes in the centers of massive galaxies are responsible for launching material that would be used in star formation into Space, ending with the ability of galaxies to form new stars.
However, the new study suggests that fusions between galaxies may also be responsible for ejecting the “fuel” of star formation into space. According to Emanuele Daddi, of the Saclay Nuclear Research Center (CEA-Saclay) in France, the new observations could lead the astronomical community to review everything it knows about how distant galaxies “die”.
“ALMA has shed new light on the mechanisms that can stop star formation in distant galaxies. Witnessing such a massive disturbance event allows us to add an important piece to the complex puzzle of galactic evolution, ”says Chiara Circosta, researcher at University College London, UK.