Over a seven year period an international team of scientists has mapped more than a quarter of the northern sky using the Low Frequency Array (LOFAR), a pan-European radio telescope. It reveals an astonishingly detailed radio image of more than 4.4 million objects and a very dynamic picture of our Universe. 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.
Published by the editorial team, 25 February 2022
A wealth of new information
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.
Each dot in this video shows the location of some hugely energetic object in our Universe. This includes black holes, galaxies with bursts of star formation, and explosive merging events between some of the Universe’s largest groups of galaxies. The video shows the most detailed ever view of our radio Universe as revealed by LOFAR. Credits Frits Sweijen.
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.
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
Leading the way to more scientific breakthroughs
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. 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.
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.
Astronomer Timothy Shimwell, ASTRON and Leiden University, says “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. This release is only 27% of the entire survey and we 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.
Full journal article: https://doi.org/10.1051/0004-6361/202142484
LOFAR surveys project: https://lofar-surveys.org
Public data repository: https://dx.doi.org/10.25606/SURF.lotss-dr2