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PARIS – The known universe is bigger and bigger.
The study used radio astronomy to examine a segment of the sky and uncovered 300,000 unseen sources of light believed to be distant galaxies.
Tuesday, a new map of the night sky has uncovered hundreds of thousands of galaxies until then unknown discovered with the help of a telescope capable of detecting light sources that optical instruments can only no see.
The international team behind this unprecedented space study said its discovery sheds new light on some of the deepest secrets in the universe, including black hole physics and how galaxy clusters are evolving. .
"This is a new window on the universe," said AFP Cyril Tasse, astronomer at the Paris Observatory and associated with the project.
"When we saw the first images, we were like," What is it ?! "It was nothing like what we are used to seeing."
More than 200 astronomers from 18 countries participated in this study, which used radio astronomy to examine a segment of the sky over the northern hemisphere and discovered 300,000 previously unseen light sources that we thought were distant galaxies.
Radioastronomy allows scientists to detect the radiation produced when massive celestial objects interact.
The team used the LOFAR (Low Frequency Array) telescope in the Netherlands to detect traces – or "jets" – of old radiation produced during the fusion of galaxies. These jets, previously undetected, can spread over millions of light years.
"Thanks to radio observations, we can detect radiation from the thin medium that exists between galaxies," said Amanda Wilber of the University of Hamburg.
"LOFAR allows us to detect many more of these sources and to understand what is feeding them."
The discovery of new light sources could also help scientists better understand the behavior of one of the most enigmatic phenomena in space.
Black holes – which exert a gravitational force so strong that any material can not escape them – emit radiation when they engulf other high mass objects such as stars and clouds. Of gas.
Mug said the new observing technique would allow astronomers to compare black holes in time to see how they form and grow.
"If you look at an active black hole, the (radiation) jets disappear after millions of years and you will not see them at a higher frequency (of light)," he said.
"But at a lower frequency, they continue to emit these jets for hundreds of millions of years, so we can see much older electrons."
"The oldest objects in the universe"
The Hubble Telescope has produced images that suggest that scientists believe that there are more than 100 billion galaxies in the universe, although many are too old and too far to be observed at the time. using traditional detection techniques.
The map created by LOFAR observations, part of which was published in the journal Astronomy & Astrophysics, contains data equivalent to ten million DVDs, but represents only two percent of the sky.
The LOFAR telescope is made up of a European network of radio antennas spread over seven countries, which is equivalent to a satellite dish with a diameter of 1,300 kilometers.
The team plans to create high-resolution images of the entire northern sky, which will reveal up to 15 million radio sources still undetected.
"The oldest objects in the universe are between 11 and 12 billion light years away," said Tasse. "So we will see many more of these objects."
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