Astronomers have found an unusual monster galaxy in the very early universe, which churned out stars at a high rate before it suddenly died, according to a study published this week.

The study, published in the latest edition of Astrophysical Journal, dubbed the galaxy as XMM-2599, which existed about 12 billion years ago.

"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 ultramassive galaxy," said the study's lead author Benjamin Forrest, with University of California Riverside (UC Riverside).

The researchers also found that the galaxy formed most of its stars in a huge frenzy when the universe was less than 1 billion years old. It formed more than 1,000 solar masses a year in stars at its peak of activity, which was an extremely high rate of star formation.

Then the galaxy became inactive by the time the universe was only 1.8 billion years old, perhaps because it stopped getting fuel or its black hole began to turn on, according to the study.

"Our results call for changes in how models turn off star formation in early galaxies," said Gillian Wilson, a professor of physics and astronomy at UC Riverside in whose lab Forrest works.

The evolutionary pathway of XMM-2599 is unclear. Michael Cooper, a professor of astronomy at UC Irvine and the study's co-author, 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," Cooper said.

The team used the powerful Multi-Object Spectrograph for Infrared Exploration at the W. M. Keck Observatory to make measurements of galaxy.


Email: lansuying@nbd.com.cn

Editor: Lan Suying