An international team of astronomers led from Chalmers University of Technology, Sweden, has used the giant radio telescope LOFAR to create the sharpest astronomical image ever taken at very long radio wavelengths. The galaxy M 82 was observed simultaneously with LOFAR stations in five countries. After the observations, the data was accessed via the LOFAR LOFAR Long-term archive (LTA), managed jointly by Target and ASTRON. The image produced from the data shows the glowing centre of the galaxy Messier 82 and many bright remnants of supernova explosions.
The Messier 82 galaxy, located just 11.5 million light years away is bustling with activity. The rate of star formation is much higher than in our own galaxy Milky Way, and many astronomers studying the evolution of stars and galaxies keep a close eye on this spot in the sky. In optical wavelengths, M 82 looks like it's swarming with stars, gas and glowing dust. The radio image produced with LOFAR looks much more barren, but only at first sight. " In LOFAR's new extremely sharp image we’re seeing a collection of bright spots, which are most likely supernova remnants", explains Eskil Varenius. "We’re surprised that LOFAR can see as many as 16 bright supernova remnants in M 82. This image can give us new clues to the structure of M 82 and why so many stars are being formed there", adds John Conway, part of the team and director of Onsala Space Observatory in Sweden.
Supernova remnants are expanding shells of shock waves created by the explosion of massive stars. They are generally very large, often bigger than our own Solar system, but look small from a distance. "This galaxy is millions of light years away, and each remnant can be as little as a few light years across. "We need extremely sharp images to study them", says Eskil Varenius. The large distance between the LOFAR stations makes it possible to see small details on the sky, comparable to the face of an astronaut on the International Space Station as seen from the Earth. By observing how different radio wavelengths interact with the plasma surrounding the supernova remnants, astronomers can learn more about the evolution of M 82 and the processes that govern star formation within the galaxy.
The LOFAR telescope is a new generation telescope that relies on massive computational resources and generates high data volumes. Target and ASTRON have jointly developed the long-term archive (LTA) where LOFAR data is stored and accessed by astronomers across the world. The archive is based on a distributed storage with data centers in Groningen, Amsterdam and Julich, Germany. Scientists use the Astro-WISE information system, developed by our partner OmegaCEN to access and process data from LOFAR, as well as share and collaborate on the development of processing pipelines and other image processing code. "The LTA is very important for my LOFAR work because I get all data through the LTA. There is a wide range of ideas about how to extract more knowledge from the data in the LTA in the future. I have also noticed that the LTA is improving with new features, which is nice for future projects." says Eskil Varenius.
Target is one of the largest ongoing public-private projects in the Netherlands in the area of large-scale data management and information systems. The project focuses on research and development of innovative intelligent information systems that can efficiently process data and extract information from extremely large and structurally diverse datasets. Target has set up an expertise center at the University of Groningen for research and development of intelligent information system that can effectively extract valuable user-specific information out of the ever-expanding ocean of Big Data. Alongside its large-scale data-intensive scientific projects (LOFAR LTA, MUSE, KiDs/VIKING, MICADO, Euclid, LineLines, GLIMPS, etc), Target is focused on translating its knowledge into viable commercial applications based on demands posed by users outside academia, including innovative small and medium enterprises, public organizations, multi-national businesses and more.
Designed and built by ASTRON, LOFAR (Low Frequency Array) is a radio telescope, which consists of thousands of antennas spread across northern Europe with its core in the Netherlands. The telescope is uniquely sensitive to the very longest radio waves that can penetrate the Earth's atmosphere. The International LOFAR Telescope has 38 stations in the Netherlands, six in Germany, and one each in France, Sweden and the United Kingdom. Three further stations are under construction in Poland.LOFAR is also a recognized science and technology pathfinder facility for the next generation radio telescope, the Square Kilometre Array (SKA).
The Research work
The research is published in the paper Subarcsecond international LOFAR radio images of the M82 nucleus at 118 MHz and 154 MHz by E. Varenius et al., to be published shortly in Astronomy & Astrophysics. A version of the paper is available online at http://arxiv.org/abs/1411.7680.
The team is comprised of Eskil Varenius (Chalmers), John E. Conway (Onsala Space Observatory, Chalmers), Ivan Martí-Vidal (Onsala Space Observatory, Chalmers), R. Beswick (University of Manchester, United Kingdom), A. T. Deller (ASTRON, Netherlands), O. Wucknitz (Max-Planck-Institut für Radioastronomie [MPIfR], Germany), N. Jackson (Manchester), B. Adebahr (MPIfR), M. A. Pérez-Torres (Instituto de Astrofísica de Andalucía, Spain), K. T. Chyży (Jagiellonian University, Krakow, Poland), Tobia D. Carozzi (Onsala Space Observatory, Chalmers), J. Moldón (ASTRON), Susanne Aalto (Chalmers), R. Beck (MPIfR), P. Best (Royal Observatory Edinburgh, United Kingdom), R.-J. Dettmar (Ruhr-Universität Bochum, Germany), W. van Driel (Observatoire de Paris, France), G. Brunetti (INAF-Istituto di Radioastronomia, Bologna, Italy), M. Brüggen (University of Hamburg, Germany), M. Haverkorn (Radboud University and Leiden University, Netherlands), G. Heald (ASTRON/KAI), Cathy Horellou (Chalmers), M. J. Jarvis (University of Oxford, United Kingdom), L. K. Morabito (Leiden University), G. K. Miley (Leiden University, Netherlands), H. J. A. Röttgering (Leiden University), M. C. Toribio (ASTRON) and G. J. White (Open University and RAL, UK).
Onsala Space Observatory Press Release
Lofar’s record-sharp image gives astronomers a new view of galaxy M 82
ASTRON Press Release
LOFAR’S Record sharp image gives astronomers a new view of galaxy M 82
High-resolution image of M82 galaxy on Flickr
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