Astronomers have 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 the Netherlands astronomical foundation ASTRON.
The team 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 George Heald identified a new, huge source that represents material ejected from one member of an interacting galaxy triplet system tens to hundreds of millions of years ago.
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.
The center of the new GRG is associated with one member of a galaxy triplet known as UGC 09555. The central galaxy is located 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 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.
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.
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.
