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Flurry of discoveries in new LOFAR image revealing 4.4 million galaxies

An international team of scientists has mapped more than a quarter of the northern sky using the pan-European radio telescope LOFAR. It reveals an astonishingly detailed radio image of more than 4.4 million objects and a very dynamic picture of our Universe. SURF’s data analytics and storage services were instrumental in achieving this result.
Whale Galaxy

See below for description of this image

The vast majority of these objects are billions of light years away and are either galaxies that harbour massive black holes or are rapidly growing new stars. Rarer objects that have been discovered include colliding groups of distant galaxies and flaring stars within the Milky Way. Now that this treasure trove of data has been made public, anyone can view the most exotic wonders of our intriguing Universe in a brand new light. 

Burst of scientific publications

The wealth of new information in the maps is evident from a burst of recent scientific publications that make use of the radio images. Astronomers from numerous institutes have explored all types of objects with these data. For example, today the team published the largest ever studies of colliding clusters of hundreds to thousands of galaxies offering new insights into magnetic fields and high energy particles in the Universe’s largest structures.

Previous results include: finding curious signals from nearby stars that may be induced by orbiting exoplanets; pin-pointing the slowest-spinning pulsar that challenges the current theories describing such objects; observing so called “jellyfish galaxies” shedding material as they travel through the surrounding medium; witnessing eruptions of black holes that shape their local environment; probing the fabric of the cosmic web through the locations and shapes of galaxies; shedding new light on the most distant super-massive black holes in the Universe; and the discovery of so many radio galaxies of all shapes, sizes and ages that a citizen science project has been set up to help find new black-holes in this zoo of objects. Whilst these discoveries are already refining our understanding of the Universe it is also clear that the work that has been conducted to-date only scratches the surface of what is to come. 

State-of-the-art data processing algorithms

To produce the map, state-of-the-art data processing algorithms were deployed on high performance computers all over Europe to process 3,500 hours of observations that occupy 8 petabytes of disk space – the equivalent to roughly 20,000 laptops. SURF’s Grid service, Spider service and Data Repository, among other systems, were instrumental in achieving this result. This data release, which is by far the largest from the LOFAR Two-metre Sky Survey, presents about a million objects that have never been seen before with any telescope and almost four million objects that are new discoveries at radio wavelengths. The data in the release can be used to search for a wide range of signals, such as those from nearby planets or galaxies right through to faint signatures in the distant Universe.

Jellyfish galaxy

A composition radio (LoTSS-DR2) and optical (Hubble space telescope) image of the “jellyfish galaxy” NGC 4858 which is flying through a dense medium that is stripping material from the galaxy. Credits Ian Roberts

Coma cluster

A composite radio (LoTSS; red) and infrared (WISE; white) image of the Coma cluster which is over 300 million light years from Earth and consists of over 1,000 individual galaxies. The radio image shows radiation from highly energetic particles that pervade the space between the galaxies. Credits Annalisa Bonafede.

Cygnus loop supernova remnant

A composition radio (LoTSS; purple), UV (GALEX; yellow) and X-ray (ROSAT; blue) image of the Cygnus loop supernova remnant. This spectacular structure in the Milky Way is something to look forward to in future LoTSS data releases as the survey is now beginning to explore our Galaxy. Credits Jennifer West

“This project is so exciting to work on. Each time we create a map our screens are filled with new discoveries and objects that have never before been seen by human eyes. Exploring the unfamiliar phenomena that glow in the energetic radio Universe is such an incredible experience and our team is thrilled to be able to release these maps publicly.”
Astronomer Timothy Shimwell, ASTRON and Leiden University

This release is only 27% of the entire survey and the researchers anticipate it will lead to many more scientific breakthroughs in the future, including examining how the largest structures in the Universe grow, how black holes form and evolve, the physics governing the formation of stars in distant galaxies and even detailing the most spectacular phases in the life of stars in our own Galaxy.

Further reading

Header image: 
Radio, X-ray and optical composite image of the “Whale Galaxy” NGC 4631. In this galaxy star-formation produces hot gas that is visible in X-ray (blue) as well as highly energetic particles that spiral in the galaxy’s magnetic field that are visible in the LoTSS radio image (orange). The high levels of star formation are possibly triggered by an interaction with a companion galaxy. Credits Volker Heesen & Michael Stein.