Excerpt from voicechronicle.com
Astronomers have discovered a dust-filled ancient galaxy from the very early universe, which debunks earlier theories that earliest galaxies had no dust but gas. Astronomers from the University of Copenhagen used the Very Large Telescope’s X-shooter instrument along with the Atacama Large Millimeter/submillimeter Array and discovered a galaxy, named Galaxy A1689-zD1, which is an ancient galaxy and far from Earth.
The astronomers stated that the galaxy which
they were surprised to discover is far more evolved system than expected. It had a fraction of dust similar to a very mature galaxy, such as the Milky Way. Such dust is vital to life, because it helps form planets, complex molecules and normal stars.
According to the astronomers A1689-zD1 is only observable by virtue of its brightness being amplified more than nine times by a gravitational lens in the form of the spectacular galaxy cluster. Without the gravitational boost, the glow from this very faint galaxy would have been too weak to detect.
The astronomers stated that they are viewing A1689-zD1 when the Universe was only about 700 million years old, which is 5% of its present age. According to them, it is a relatively modest system — much less massive and luminous than many other objects that have been studied before at this stage in the early universe and hence a more typical example of a galaxy at that time.
A1689-zD1 is being observed as it was during the period of reionization, when the earliest stars brought with them a cosmic dawn, illuminating for the first time an immense and transparent universe and ending the extended stagnation of the Dark Ages. Expected to look like a newly formed system, the galaxy surprised the observers with its rich chemical complexity and abundance of interstellar dust.
Dust plays an extremely important role in the universe – both in the formation of planets and new stars.
Darach Watson, Associate Professor at Dark Cosmology Centre, University of Copenhagen, and the lead author of the study, said, “After confirming the galaxy’s distance using the VLT we realized it had previously been observed with ALMA. We didn’t expect to find much, but I can tell you we were all quite excited when we realized that not only had ALMA observed it, but that there was a clear detection. One of the main goals of the ALMA Observatory was to find galaxies in the early Universe from their cold gas and dust emissions — and here we had it!”
The researchers hope that future observations of a large number of distant galaxies could help unravel how frequently such evolved galaxies occur in this very early epoch of the history of the universe.