Print this page

New giant galaxy discovered by SKA pathfinder LOFAR telescope

19 March 2013, Dwingeloo, the Netherlands – A team of astronomers led by ASTRON astronomer Dr. George Heald has discovered a previously unknown gigantic radio galaxy, using initial images from a new, ongoing all-sky radio survey. The galaxy was found using the powerful International LOFAR Telescope (ILT), built and designed by ASTRON. The LOFAR telescope is an important scientific and technological pathfinder for the world’s largest radio telescope – the Square Kilometre Array (SKA). The team led by Dr. Heald is currently performing LOFAR’s first all-sky imaging survey, the Multi-frequency Snapshot Sky Survey (MSSS). While browsing the first set of MSSS images, Dr. Heald identified a new source the size of the full moon projected on the sky. The radio emission is associated with material ejected from one member of an interacting galaxy triplet system tens to hundreds of millions of years ago. The physical extent of the material is much larger than the galaxy system itself, extending millions of light years across intergalactic space. The MSSS survey is still ongoing, and is poised to discover many new sources like this one.

Overlay of the new GRG (blue-white colors) on an optical image from the Digitized Sky survey. The inset shows the central galaxy triplet (image from Sloan Digital Sky Survey). The image is about 2 Mpc across.

The new galaxy is a member of a class of objects called Giant Radio Galaxies (GRGs). GRGs are a type of radio galaxy with extremely large physical size, suggesting that they are either very powerful or very old. LOFAR is an effective tool to find new GRGs like this one because of its extreme sensitivity to such large objects, combined with its operation at low frequencies that are well suited to observing old sources.

The center of the new GRG is associated with one member of a galaxy triplet known as UGC 09555. The central galaxy is located at a redshift of z=0.054536, or 750 million light years from Earth. The central radio source was previously known and has a flat radio spectrum, typical of giant radio galaxies.

LOFAR’s MSSS survey is a concerted effort to image the entire northern sky at very low radio frequencies, between 30 and 160 MHz (wavelengths from 2m to 10m). The primary aim of the survey is to perform an initial shallow scan of the sky, in order to create an all-sky model that will support the calibration of much deeper observations. It is comparable in sensitivity and angular resolution to previous surveys with ‘classical’ radio telescopes like the Very Large Array (VLA) in the USA, ASTRON’s Westerbork Synthesis Radio Telescope (WSRT), and the Giant Metrewave Radio Telescope (GMRT) in India. MSSS is unique in that it operates at substantially lower frequencies, and is therefore poised to uncover new sources that were missed by previous surveys. Its broad bandwidth coverage is also novel in all-sky radio surveys, and will be used to provide additional information about the detected objects.

The international team of astronomers that is performing the MSSS survey is made up of about fifty members from various institutes, mostly in the Netherlands, Germany, the UK, Poland, France and Italy.

More information about MSSS: http://www.astron.nl/radio-observatory/lofar-msss/lofar-msss

About ASTRON

ASTRON is the Netherlands Institute for Radio Astronomy, part of the Netherlands Organisation for Scientific Research (NWO). Its mission is to make discoveries in radio astronomy happen, via the development of novel and innovative technologies, the operation of world-class radio astronomy facilities, and the pursuit of fundamental astronomical research. See also: www.astron.nl.

About the SKA

The Square Kilometre Array will be the world’s largest and most sensitive radio telescope. The total collecting area will be approximately one square kilometre giving 50 times the sensitivity, and 10 000 times the survey speed, of the best current-day telescopes. The SKA will be built in Southern Africa and in Australia. Thousands of receptors will extend to distances of 3 000 km from the central regions. The SKA will address fundamental unanswered questions about our Universe including how the first stars and galaxies formed after the big bang, how dark energy is accelerating the expansion of the Universe, the role of magnetism in the cosmos, the nature of gravity, and the search for life beyond Earth. Construction of phase one of the SKA is scheduled to start in 2016. The SKA Organisation, with its headquarters at Jodrell Bank Observatory, near Manchester, UK, was established in December 2011 as a not-for-profit company in order to formalise relationships between the international partners and centralise the leadership of the project.

Members of the SKA Organisation as of March 2013:

  • Australia: Department of Innovation, Industry, Science and Research
  • Canada: National Research Council
  • China: Ministry of Science and Technology
  • Germany: Federal Ministry of Education and Research
  • Italy: National Institute for Astrophysics
  • Netherlands: Netherlands Organisation for Scientific Research
  • New Zealand: Ministry of Economic Development
  • Republic of South Africa: National Research Foundation
  • Sweden: Onsala Space Observatory
  • United Kingdom: Science and Technology Facilities Council

Associate member:

  • India: National Centre for Radio Astrophysics

SKA website: www.skatelescope.org

For more information about this release and ASTRON:
Femke Boekhorst, PR & Communication, ASTRON: +31 521 595 204 and +31 6 21 23 42 43. E-mail: boekhorst@astron.nl
Dr. George Heald, astronomer. Phone: +31 521 595 100. E-mail: heald@astron.nl

For more information about the SKA:
William Garnier, Chief Communications Officer, SKA: +44 (0) 161 306 9613 and + 44 (9) 7814 908 932. E-mail: w.garnier@skatelescope.org

 

Share on Facebook0Share on Google+0Share on LinkedIn0Tweet about this on Twitter19Email this to someone