In a new study, published in the Astrophysical Journal on Wednesday, astronomers have spotted an ultramassive monster galaxy, dubbed XMM-2599, dating back to the early days of the universe which lived fast and died young.
The astronomers used the Multi-Object Spectrograph for Infrared Exploration at W M Keck Observatory in Hawaii to get detailed measurements that suggest the galaxy rapidly formed a bunch of stars and died.
XMM-2599: the ultra massive galaxy
Benjamin Forrest, lead study author and a postdoctoral researcher in the University of California, Riverside's Department of Physics and Astronomy, said, "Even before the universe was 2 billion years old, XMM-2599 had already formed a mass of more than 300 billion suns, making it an ultra massive galaxy."
"More remarkably, we show that XMM-2599 formed most of its stars in a huge frenzy when the universe was less than 1 billion years old and then became inactive by the time the universe was only 1.8 billion years old," the study author added.
Created over 1,000 solar masses of stars in a year
The galaxy, which existed 12 billion years ago, created more than 1,000 solar masses of stars in a year during its prime days. According to the researchers, this rate of star formation is incredibly high when compared to the Milky Way that forms one new star in a year.
"XMM-2599 may be a descendant of a population of high star-forming, dusty galaxies in the very early universe that new infrared telescopes have recently discovered," said Danilo Marchesini, study co-author and an associate professor of astronomy at Tufts University in Massachusetts.
Should XMM-2599 still form stars?
However, the astronomers are not sure of the evolution of the unusually huge galaxy. Based on their models, they said that XMM-2599 should still be forming stars. Gillian Wilson, a professor of physics and astronomy at the University of California, Riverside, said, "What makes XMM-2599 so interesting, unusual and surprising is that it is no longer forming stars, perhaps because it stopped getting fuel or its black hole began to turn on."
"Our results call for changes in how models turn off star formation in early galaxies. We have caught XMM-2599 in its inactive phase," Wilson added. The astronomers said that the galaxy is not forming any more stars, but it can't lose its mass. Wilson said, "As time goes by, could it gravitationally attract nearby star-forming galaxies and become a bright city of galaxies?"
Co-author Michael Cooper, an associate professor of astronomy at UC Irvine, said, "Perhaps during the following 11.7 billion years of cosmic history, XMM-2599 will become the central member of one of the brightest and most massive clusters of galaxies in the local universe. Alternatively, it could continue to exist in isolation. Or we could have a scenario that lies between these two outcomes."
The astronomers will continue to study the strange galaxy at the observatory and they are hopeful that they will get the unanswered questions prompted by XMM-259.