The team is of the opinion that the gas ejection is due to the collision of two galaxies. (Image: ESO/M. Kornmesser)
Galaxy death: When stars stop forming in a galaxy, that marks the beginning of the death of that galaxy. This is something scientists have known for long, but they had never witnessed this happening clearly in a far away galaxy. Until now. A team of astronomers has now been able to witness a galaxy eject about half of its gas which was capable of forming stars. The team managed to see this phenomenon with the help of the European Southern Observatory (ESO)-powered Atacama Large Millimeter/submillimeter Array (ALMA). The research has been published in the journal Nature Astronomy and has been accessed by Financial Express Online.
In a statement, the ESO said that the galaxy is ejecting the gas at an alarming rate. Currently, the galaxy is ejecting gas equivalent to 10,000 Suns every year, meaning that it is very quickly losing its fuel to make new stars. According to the astronomers, the galaxy started losing its gas after it collided with another galaxy, potentially bringing a change in the astronomers’ beliefs on what causes galaxies to end.
The galaxy called ID2299 is at a distance of 9 billion light years from the Earth, which means that the galaxy’s light takes 9 billion years to reach the Earth, and what the astronomers have witnessed now had actually taken place when the universe was only about 4.5 billion years old.
The statement by ESO quoted study’s lead researcher Annagrazia Puglisi as saying that this marks the first time astronomers have witnessed the beginning of the death of a massive star-forming galaxy at such a vast distance due to a huge amount of cold gas ejection.
Since the event is currently taking place from the Earth’s perspective, the astronomers believe that the galaxy would reach its end in another few tens of millions of years, since the ID2299 is losing its gas at a whopping rate of 46%, while the remaining gas is being used to form stars. What makes things worse is that the galaxy is forming stars at a much faster rate than the Milky Way, quickly exhausting the gas of ID2299.
The team is of the opinion that the gas ejection is due to the collision of two galaxies, which merged to form the ID2299. Scientists were able to find out about this collision when they happened to catch an elongated stream of gas and stars extending into space. This phenomenon is called ‘tidal tail’ and is usually very faint to be captured at such a distance, but astronomers saw this when the event was still bright because it was just being launched into space.