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Low-frequency waves help astronomers click faraway galaxy

IANS | Last Updated: Saturday, August 23, 2014 - 13:34

London: A team of astronomers has taken the most sensitive image of a galaxy 30 million light years away via a radio telescope with frequencies just above those of commercial FM radio stations.

The European astronomers took images of `Whirlpool Galaxy` Messier 51 (M51) with the Low Frequency Array (LOFAR) radio telescope in the frequency range 115-175 MHz that is just above the normal commercial FM radio frequency band of 88-108 MHz.

Radio astronomy has not been able to explore low frequencies below 300 MHz because the ionosphere around the Earth acts as a barrier of low-frequency radio waves.

The only observations were of poor resolution and no details could be made out.
"Low-frequency radio waves are important as they carry information about electrons of relatively low energies that are able to propagate further away from their places of origin in the star-forming spiral arms and are able to illuminate the magnetic fields in the outer parts of galaxies," said David Mulcahy from the University of Southampton`s astronomy group.

The signals from all stations of LOFAR spreading across the Netherlands, Germany, Britain, France and Sweden were combined in a powerful computing cluster located at University of Groningen in the Netherlands.

With LOFAR`s high sensitivity, the astronomers detected electrons and magnetic fields in the spiral arms and extended disc of M51, 40,000 light years away from the galaxy`s centre - much further out than had ever been traced before.
Radio astronomy shows two crucial components of galaxies that are invisible to optical telescopes - cosmic ray electrons and magnetic fields - which play an important role in the stability and evolution of galaxies.

The research is published in the journal Astronomy & Astrophysics.

First Published: Saturday, August 23, 2014 - 13:25
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