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Astronomers chart new map of night sky

Scientists believe the discovery of new stars and galaxies could help them better understand black holes
by TR Pakistan

A new map of the sky includes 300,000 previously unknown galaxies, which were discovered using the Low Frequency Array (LOFAR) telescope network in the Netherlands.

“This is a new window on the universe,” said Cyril Tasse, an astronomer at the Paris Observatory who was involved in the project. “When we saw the first images we were like: ‘What is this?!’ It didn’t look anything at all like what we are used to seeing.”

Over 200 astronomers from 18 different countries were involved in the study.

LOFAR used its array of 20,000 antennas spread across 48 stations in the Netherlands to collect this data by detecting radiation which is released when large celestial objects interact. The signals it picks up are known as “jets” and can extend for millions of light years.

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“With radio observations we can detect radiation from the tenuous me­­dium that exists between galaxies,” said Amanda Wilber, of the University of Hamburg. “LOFAR allows us to detect many more of these sources and understand what is powering them.”

LOFAR’s task included an intensive survey of the northern night sky at radio frequencies of around 120 to 168 megahertz. It was expected this would provide new information on a variety of softly shining astronomical phenomena.

So far, only 20 percent of this survey has been completed. Furthermore, global scientists can only access 10 percent of the data available but a lot of work has already been done on this small set of information. The journal Astronomy and Astrophysics has published 26 studies based on this initial release. They cover a wide array of topics including quasars, blazars, black holes, and intergalactic electromagnetic fields.

Scientists believe that this newly discovered data will also help them better understand black holes. Black holes also emit radiation when they swallow other high mass objects such as stars and gas clouds.

“If you look at an active black hole, the jets [of radiation] disappear after millions of years, and you won’t see them at a higher frequency [of light],” Tasse said. “But at a lower frequency they continue to emit these jets for hundreds of millions of years, so we can see far older electrons.”