A team of scientists have discovered that some of the earliest galaxies in the universe may have also been early bloomers. The team found that these early galaxies matured faster compared to some of the later galaxies.
Back in the early days of the universe, the first galaxies may have exhibited a higher rate of star formation. The researchers conducting the study were able to observe a total of 15 mature galaxies very far from our own. The findings of the study were published in the online journal The Astrophysical Journal Letters.
"These distant and early massive galaxies are one of the Holy Grails of astronomy," said Karl Glazebrook, the director of the Centre for Astrophysics and Supercomputing in the Swinburne University of Technology.
The astronomers found the mature galaxies at a distance of 12 billion light years away. This is considered as a huge achievement for astronomy since the mature galaxies were found at a distance that broke previous records. At this distance, we are actually seeing the image of the galaxies at a time when they were only around 1.6 billion years old, which would be considered very young for a galaxy.
"Fifteen years ago they were predicted not to even exist within the cosmological model favored at the time," said Glazebrook. "In 2004 I wrote a paper on the discovery of such galaxies existing only three billion years after the Big Bang. Now, with improved technology we are pushing back to only 1.6 billion years, which is truly exciting."
Considering that the astronomers were studying images of galaxies less than two billion years old, the researchers were surprised that the size, scale and maturity of these distant galaxies. To reach this level of maturity in a relatively short time period, the galaxies must have gone through a period of rapid star birth.
"While the Milky Way still forms new stars at a slow rate today, the galaxies we discovered must have formed very rapidly in a relatively 'short' time - roughly one billion years - with explosive rates of star-formation," said Lee Spitler, a lecturer from the Macquarie University. "These must have been several hundred times higher than in the Milky Way today."
The international team of researchers found the distant galaxies after a grueling 40 nights of searching using the Magellan Baade Telescope located in Chile. The team also used images taken by the space observatory Hubble to supplement their study.
"This is the best evidence to date that these galaxies grew up in a hurry. People have reported 'old' galaxies before, but it was never clear until our data that they were actually 'old'," added Spitler. The excellent imaging products from the Magellan telescope allowed us to prove they are indeed 'old'."
