February 09 : Astronomers recently found that a monster galaxy existed when the universe was just 1.8 billion years old, approximately 12 billion years ago. This galaxy created stars at extremely high rate and then became inactive.
Monster galaxy XMM-2599
A team of astronomers led by the scientists at the University of California (UC), discovered that galaxy XMM-2599 was quite unusual. The research found that before XMM-2599 galaxy died, it formed more than 300 billion suns, turning into an ultra-massive galaxy. Benjamin Forrest, a researcher in UC, said XMM-2599 formed most of the stars instantly when the universe was less than 1 billion years old. Suddenly, it became inactive when it was only 1.8 billion years old.
Massive galaxies like XMM-2599 are rare in this era
Gillian Wilson, professor of physics and astronomy at UC, said in this era there are many galaxies but none are as huge as XMM-2599, and not many have stopped forming stars. Massive galaxies like XMM-2599 are unimaginably rare in this era, Wilson added, but still they are predicted by numerical models. However, XMM-2599 literally challenged all numerical models. The astronomers found that the predicted galaxies are still actively forming stars.
What makes XMM-2599 unusual?
The fact that made XMM-2599 interesting and unusual is that it suddenly stopped forming stars. The astronomers believe there could be two reasons—either it failed to get fuel or its black hole started turning on.
Another fact that made XMM-2599 unusual is that the galaxy created more than 1,000 solar masses a year in stars when it was at the peak of activity, which is an exceptionally high rate of star formation. In comparison, the Milky Way creates just one star a year. The team believes XMM-2599 must have been an offshoot of highly star-forming dusty galaxies.
Researchers said that if XMM-2599 was active to date, it could have gravitationally attracted its neighbouring star-forming galaxies and become a city of galaxies. There was another possibility that XMM-2599 could have become the main galaxy of a cluster of massive galaxies in the universe.