KAT-7 scopes out Centaurus

All seven of the KAT-7 telescope’s have been fitted with ‘cold’ radio receivers, bringing the first images of the Centaurus A galaxy down to earth.

The KAT-7 telescope, a prototype for the MeerKAT radio telescope array being built by the SKA South Africa team on the Karoo Astronomy Reserve, has achieved a major milestone. All seven of the dishes have now been successfully fitted with ‚cold‚ radio receivers, signaling the successful completion of the telescope antennas.

The first astronomical image has already been made using cold receivers on all seven KAT-7 dishes. The radio galaxy Centaurus A, whose intense radio emission is powered by a massive black hole in the centre of the galaxy, was selected for this purpose. The resulting image is much more sensitive than the preliminary image made with just four of the KAT-7 dishes fitted with un-cooled receivers in 2010. This improvement is due to both the cooling of the receivers and the availability of all seven dishes of the array.

The radio receivers and all their components are cooled to about 70 Kelvin (i.e. minus 203 Celsius) in order to reduce the ‚noise‚ which is inherent in all radio (and TV) receivers. This allows the telescope to see much fainter objects than it would if the receivers and ‚feeds‚ operated at room temperature and were not cooled.

Cooling improves the sensitivity of the receivers by more than a factor of 2.5, which in turn reduces the observation time to achieve a given image quality by more than a factor of 6. This improvement in performance will allow KAT-7 to perform early science in preparation for the MeerKAT and SKA. These preliminary observations will be focused on the needs of the MeerKAT large survey projects, and include imaging of nearby galaxies and work on radio transients and pulsars, for which KAT-7 is well suited.

KAT-7 tests technology for the MeerKAT, which is in its early construction phase and is due for completion in 2016. The MeerKAT will be among the most powerful telescopes in the world and is an important step towards the realization of the SKA. It will provide African scientists and engineers with a cutting-edge instrument for revolutionary science and technology.

MeerKAT Project Manager Willem Esterhuyse said ‚This latest milestone in the development of the KAT-7 telescope has again been achieved on schedule. The technical staff on the site, Siyabulela Tshongweni, Sibusiso Wakhaba, Andre Walker and Matthys Maree have worked with great commitment, together with the rest of the SKA SA team, Stellenbosch company EMSS and Cape Town company Tellumat, to achieve this goal. All four technicians have been trained in their special high-tech skills by the SKA SA project.‚

* Read more about MeerKAT and KAT-7 here: MeerKAT passes first test

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