Astronomers Reveal Incredible Map of 4.4 Million Galaxies

Durham University astronomer collaborating with a team of international scientists have mapped more than a quarter of the northern sky using the Low-Frequency Array (LOFAR), a pan-European radio telescope.  

The map reveals an astonishingly detailed radio image of more than 4.4 million objects and a very dynamic picture of our Universe, which now has been made public for the first time.

The vast majority of these objects are billions of light-years away and are either galaxies that harbor 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.

To produce the map, scientists deployed state-of-the-art data processing algorithms 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.

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. Credit: Ian Roberts

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.

This innocuous looking red quasar is one of the most powerful objects in the early Universe and was formed within 1 billion years of the Big Bang. Here we see the quasar as it looked 12.9 billion years ago when its central black hole was rapidly accreting material and creating powerful outbursts that glow at radio wavelengths. We do not yet fully understand how such powerful sources formed so soon after the Big Bang. Credit: Anniek Gloudemans

Astronomer Timothy Shimwell of ASTRON and Leiden University, said: “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.”

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. Credit: Annalisa Bonafede

Durham University scientist, Dr. Leah Morabito, said: “We’ve opened the door to new discoveries with this project, and future work will follow up these new discoveries in even more detail with techniques, which we work on here at Durham as part of the LOFAR-UK collaboration, to post-process the data with 20 times better resolution.”

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. Credit: Volker Heesen & Michael Stein

This image shows the dynamic highly energetic radio wavelength Universe. It is a 9 square degree cutout image of LoTSS-DR2 showing a region dominated by the radio galaxies NGC 315 and NGC 383 but containing about 7,000 other astronomical sources of radio radiation. The image covers an area that is 45 times larger than that of the full moon but corresponds to only 1.5% of the total amount of data released in LoTSS-DR2. Essentially all the objects that are visible lie in the distant Universe and are powerful, explosive phenomena such as jets of radiation from supermassive black holes and galaxies where stars are rapidly forming. Credit: Timothy Shimwell

Each panel in this high resolution montage shows radio wavelength radiation produced when two giant clusters of 100s to 1000s of galaxies collide. These rare events are the most energetic since the big bang and produce gigantic shock waves and turbulence spanning millions of light years. The LoTSS-DR2 cluster survey has studied 309 galaxy clusters in the largest study of its kind and furthered our understanding of these highly energetic processes. Credit: Andrea Botteon

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. Credit” Jennifer West

This data presents a major step forward in astrophysics and 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.

Each dot in this animation shows the location of a 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 animation shows the most detailed ever view of our radio Universe as revealed by LOFAR. Credit: Frits Sweijen

Reference: “The LOFAR Two-metre Sky Survey – V. Second data release” by T. W. Shimwell, M. J. Hardcastle, C. Tasse, P. N. Best, H. J. A. Röttgering, W. L. Williams, A. Botteon, A. Drabent, A. Mechev, A. Shulevski, R. J. van Weeren, L. Bester, M. Brüggen, G. Brunetti, J. R. Callingham, K. T. Chyzy, J. E. Conway, T. J. Dijkema, K. Duncan, F. de Gasperin, C. L. Hale, M. Haverkorn, B. Hugo, N. Jackson, M. Mevius, G. K. Miley, L. K. Morabito, R. Morganti, A. Offringa, J. B. R. Oonk, D. Rafferty, J. Sabater, D. J. B. Smith, D. J. Schwarz, O. Smirnov, S. P. O’Sullivan, H. Vedantham, G. J. White, J. G. Albert, L. Alegre, B. Asabere, D. J. Bacon, A. Bonafede, E. Bonnassieux, M. Brienza, M. Bilicki, M. Bonato, G. Calistro Rivera, R. Cassano, R. Cochrane, J. H. Croston, V. Cuciti, D. Dallacasa, A. Danezi, R. J. Dettmar, G. Di Gennaro, H. W. Edler, T. A. Enßlin, K. L. Emig, T. M. O. Franzen, C. García-Vergara, Y. G. Grange, G. Gürkan, M. Hajduk, G. Heald, V. Heesen, D. N. Hoang, M. Hoeft, C. Horellou, M. Iacobelli, M. Jamrozy, V. Jelic, R. Kondapally, P. Kukreti, M. Kunert-Bajraszewska, M. Magliocchetti, V. Mahatma, K. Malek, S. Mandal, F. Massaro, Z. Meyer-Zhao, B. Mingo, R. I. J. Mostert, D. G. Nair, S. J. Nakoneczny, B. Nikiel-Wroczynski, E. Orrú, U. Pajdosz-Smierciak, T. Pasini, I. Prandoni, H. E. van Piggelen, K. Rajpurohit, E. Retana-Montenegro, C. J. Riseley, A. Rowlinson, A. Saxena, C. Schrijvers, F. Sweijen, T. M. Siewert, R. Timmerman, M. Vaccari, J. Vink, J. L. West, A. Wolowska, X. Zhang and J. Zheng, 25 February 2022, Astronomy and Astrophysics.
DOI: 10.1051/0004-6361/202142484