A group of 200 astronomers from 18 different countries conducted a radio sky survey using a Low Frequency Array telescope, also known as the LOFAR telescope. Their first results were published this week, together with 26 research papers in the Astronomy & Astrophysics journal. The LOFAR telescope is used for sensitive and low radio frequency research.
Optical light is not always the best way of seeing everything that exists in the universe. Instead, scientists often refer to radio astronomy which covers a wider frequency specter. The 300,000 new signals from the distant universe were almost all from galaxies. However, the researchers also saw black holes, which helps reveal more about the evolution of galaxy clusters and measure magnetic fields.
“LOFAR has a remarkable sensitivity and that allows us to see that these jets are present in all of the most massive galaxies, which means that their black holes never stop eating,” Philip Best, one of the study authors and a professor at the University of Edinburgh’s School of Physics and Astronomy said in a statement.
Galaxy clusters look similar to huge stars, but consist of hundreds or thousands of galaxies. At times, two galaxies would merge, spreading huge radio emissions which can travel millions of light years, because of how many particles accelerated due to the merger.
“What we are beginning to see with LOFAR is that, in some cases, clusters of galaxies that are not merging can also show this emission, albeit at a very low level that was previously undetectable. This discovery tells us that, besides merger events, there are other phenomena that can trigger particle acceleration over huge scales,” said Annalisa Bonafede, associate professor in the University of Bologna’s Department of Physics and Astronomy.
The LOFAR telescope also allows astronomers to track weak magnetic fields in space, and their impact on radio waves.
“The unprecedented accuracy of the LOFAR measurements has allowed us to measure the effect of cosmic magnetic fields on radio waves from a giant radio galaxy that is 11 million light-years in size. This work shows how we can use LOFAR to help us understand the origin of cosmic magnetic fields,” said Shane O’Sullivan, professor at the University of Hamburg.
To process all the data, the team used the supercomputer and data center at SURF, a Dutch organization which works with information and communications technology, processing all the radio wave data in a year. This process would normally take much longer on a traditional computer.
“These images are now public and will allow astronomers to study the evolution of galaxies in unprecedented detail,” said Timothy Shimwell, a staff member at ASTRON.
The papers published this week only make up 2% of the sky survey’s performance. Scientists are hopeful to gather images of the entire northern skies, believing they’ll find much more than the 300,000 new signals from deep space. The team hopes these findings will help discover how the universe was formed and where supermassive black holes came from.