As they observed a massive cloud of galaxies, by coincidence a group of astronomers managed to identify a new and amazingly bright galaxy very far away, which they called SMM J2135-0102.
The discovery, made from the Llano de Chajnator at an altitude of 5,100 meters above sea level in Northern Chile’s Atacama Desert, was made possible with the use of the Atacama Pathfinder Experiment (APEX), which depends on the European Southern Observatory (ESO).
The institution revealed the discovery in a press release and explained the technique that had been used, which is similar to the one that the ALMA (Atacama Large Millimeter/submillimeter Array) will use, the largest astronomical project currently under construction, which will be built in the Atacama Desert, an area known for the clearness of its skies.
“We were amazed when we discovered a surprisingly bright object that was not where it had been expected. Suddenly we realized that it was an unknown galaxy that was further away and was being amplified by the closer cloud of galaxies,” Explained Carlos de Breuck, a researcher at the ESO.
This reveals the agitated and vigorous way that galaxies are formed, with stars born at a rate that is 100 times faster than what can be observed in younger galaxies.
The distance is so great and the light takes so long to arrive that the image of the new galaxy corresponds to a picture of the way it looked 10 billion years ago. A veritable cosmic “gravitational lens” augments the galaxy’s size and provides a close-up that would otherwise be impossible to make out.
In this way they also managed to observe the star-forming clouds on a scale of just a few hundred light years away; in other words, on a similar scale as the giant clouds in our own Milky Way.
“The enlargement reveals the galaxy in unprecedented detail, especially considering that it is so far away that its light took around 10 billion years to reach us,” said Mark Swinbank of the University of Durham, the main author of the publication on the discovery, which will be published on the website of the magazine Nature.
The astronomers see galaxies as star factories. In the particular case of this discovery, these “factories” are similar in size to the Milky Way, though 100 times brighter, which leads to the assumption that the stars were created at a far faster rate in the early days of these galaxies than in galaxies that are closer in both space and time.
“We estimate that SMM J2135-0102 is producing stars at a rate equivalent to 250 suns per year,” Breuck said. “The formation of stars in its great dust clouds is different to that of the nearby Universe, but our observations also suggest that we ought to be able to use similar fundaments of physics on the densest nuclei in nearby galaxies to understand the birth of stars in these faraway galaxies.”
With this discovery, the skies above northern Chile once again become the ideal place for astronomical progress. On previous occasions pictures have been taken of the first planet outside the solar system and primitive stars in the Milky Way. To further develop the natural advantages that the country offers, currently Chile is competing to build the largest telescope in the world, a decision that will be made in the coming months.
This post is also available in Spanish