Astronomers have first witnessed the death of a distant galaxy, which they describe as a “truly extreme event.”
When all the stars in a galaxy die and no more are created, the galaxy itself ceases to exist. This happens when all the gas of 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 Atacama Large Millimeter / submilimeter Array of telescopes in Chile.
It took about nine billion years for light from starburst galaxy ID2299 to reach Earth. So when astronomers happened to observe it, they witnessed the universe as it appeared at only 4.5 billion years old.
Astronomers say ID2299 loses 10,000 suns of gas every year – the quickly depleted fuel needed to form new stars. These startling gas releases appear to be the result of two galaxies forcibly colliding and fusing to create ID2299.
The Milky Way is also currently forming stars at a speed hundreds of times faster than the Milky Way, consuming the rest of its precious gas supply. Because of this, ID2299 is expected to die relatively quickly, in just a few tens of thousands of years.
European Southern Observatory
“This is the first time we have observed a typical massive star-forming galaxy in the distant universe that is about to ‘die’ as a result of massive cold gas emissions,” lead author Annagrazia Puglisi said in a statement.
Astronomers believe the phenomenon is the result of galaxies merging, as they witnessed a rare “tidal tail,” which is usually too faint to see in distant galaxies. This elongated stream of stars and gas, astronomers suggest, is the direct result of the galactic amalgamation.
They only observed the Milky Way for a few minutes, but it was enough to see the elusive tide tail.
“Our study suggests that gas emissions may be caused by mergers and that winds and tidal tails may be very similar,” said study co-author Emanuele Daddi. This could lead us to rethink our understanding of how galaxies ‘die.’ ‘
If the astronomers are right that the fusion led to the massive gas loss, they will have to rethink previous theories of how galaxies form and evolve – and how they die. Other theories have suggested that winds from active black holes or intense star formations are responsible for such deaths.
“Studying this single case revealed the possibility that events like this are not at all unusual and that many galaxies were suffering from this ‘gravitational gas removal,’ including misinterpreted observations from the past,” said study co-author Dr. Jeremy Fensch.
“This could have major implications for our understanding of what actually shapes the evolution of galaxies.”