14 DAY TRIAL // A research paper by experts at the Tufts University proposes that the most massive galaxies which developed in the early Universe are, or were, in fact billions of years older than first calculated.
The conclusion the group arrived at goes against current scientific models that predict how galaxies appear and evolve, and also against models showing how the early Universe looked like.
The international Tufts-led team also featured researchers from the Yale University, the Carnegie Observatories, the Leiden University, the Princeton University, the University of Kansas and the University of California in Santa Cruz (UCSC).
Details of the research appear in the November 24 online issue of the esteemed Astrophysical Journal. The study will be published in print as well, in the December 10 issue of the scientific magazine.
“We have found a relatively large number of very massive, highly luminous galaxies that existed almost 12 billion years ago when the Universe was still very young, about 1.5 billion years old,” explains scientist Danilo Marchesini.
“These results appear to disagree with the latest predictions from models of galaxy formation and evolution,” he adds. The expert holds an appointment as an astrophysicist at Tufts, and he is also the lead author of the new research paper.
“Current understanding of the physical processes responsible in forming such massive galaxies has difficulty reproducing these observations,” says the expert, who also holds an appointment as an assistant professor of physics and astronomy at the Tufts School of Arts and Sciences.
For the new research, the team focused on tracking down galaxies that existed at a time when the entire Universe was only 1.5 and 2 billion years old. This period comes right after the reionization epoch, at the end of which many galaxies began developing.
All of the structures that were analyzed in the research were between 5 and 10 times more massive then our galaxy is today. Some 80 percent of the structures had very high infrared luminosities.
This hints at the fact that they are highly active, and also in a phase of intense growth, which means that they are producing new stars at a frantic pace.
In the local Universe – the area adjacent to the Milky Way – galaxies are a lot more settled down, and none of them produces spectacular numbers of new stars.
“Either way, it is clear that our understanding of how massive galaxies form is still far from satisfactory,” Marchesini says. The new study was made possible by funding secured from the US National Science Foundation (NSF).