Astronomers have witnessed for the first time the death of a distant galaxy, which they describe as a “truly extreme event.”
When all the stars in the galaxy die and new ones no longer form, the galaxy itself ceases to exist. This happens when all the gas in the galaxy is expelled, making it impossible for new stars to form.
According to a study published Monday in the journal Nature Astronomy, scientists were “excited” to be able to capture this rare phenomenon recently using the massive Atacama Large Millimeter / Submilimeter Array telescope on telescopes in Chile.
It takes about nine billion years for the light from the galaxy ID2299 from the stellar burst to reach Earth. So when astronomers accidentally observe it, they witness the universe, as it appears only 4.5 billion years ago.
Astronomers say ID2299 loses 1
The galaxy is currently forming stars hundreds of times faster than the Milky Way – consuming the rest of its precious gas reserves. Therefore, ID2299 is expected to die relatively soon, in just a few tens of thousands of years.
“For the first time, we are witnessing a typical massive star-forming galaxy in the distant universe, which will soon” die “due to a massive discharge of cold gas,” said lead author Anagrazia Puglisi.
Astronomers believe the phenomenon was the result of a merger of galaxies, as they were able to witness a sparse “tidal tail”, usually too weak to be seen in distant galaxies. This extended flow of stars and gas, astronomers suggest, is the direct result of galactic fusion.
They observed the galaxy for only a few minutes, but that was enough to notice the elusive tidal tail.
“Our study suggests that gas emissions may be the result of mergers and that winds and tidal tails may look very similar,” said study co-author Emanuele Dadi. This could lead us to reconsider our understanding of how galaxies “die.”
If astronomers are right that the merger has led to huge gas losses, they will have to reconsider previous theories about how galaxies form and evolve – and how they die. Other theories suggest that wind from active black holes or intense star formations are responsible for such deaths.
“Investigating this single case has revealed the possibility that this type of event is not at all unusual and that many galaxies have suffered from this ‘gravitational gas removal’, including misinterpreted past observations,” said co-author Dr Jeremy Fensh.
“This could have huge implications for our understanding of what actually shapes the evolution of galaxies.”