Scientific paper shows SKA capability


A scientific paper recently accepted by the journal Monthly Notices of the Royal Astronomy Society showcases the South African Square Kilometre Array (SKA) project’s capability of building the Southern Hemisphere’s most sensitive radio telescope.

The lead author of the scientific paper, titled “A return to strong radio flaring by Circinus X-1 observed with the Karoo Array Telescope test array KAT-7”, is Dr Richard Armstrong, a SKA SA fellow at the University of Cape Town (UCT).

Construction of the SKA project is in full swing, with the first MeerKAT antenna set to be installed by the end of the year, and all 64 dishes by the end of 2016.

Armstrong explains that the new KAT-7 telescope in the Karoo – the MeerKAT’s precursor – and the existing 26m radio telescope at the Hartebeesthoek Radio Astronomy Observatory (HartRAO) were used to observe a neutron star system known as Circinus X-1, as it fires energetic matter from its core in extensive, compact jets that flare brightly. The details of the flares are visible only in radio waves.
“During the time that KAT-7 observed Circinus X-1 (13 December 2011 to 16 January 2012), the system flared twice at levels among the highest observed in recent years,” says Armstrong. “KAT-7 was able to catch both of these flares and follow them as they progressed. This is the first time the system has been observed in such detail during multiple flare cycles.”

According to Armstrong, the findings in this paper demonstrate that the SKA project is fully capable of building what will be the Southern Hemisphere’s most sensitive radio telescope (MeerKAT) by 2016. “[It also shows] we have much to contribute to the design of the SKA itself, which will of course be predominantly based in SA.”

Armstrong left the UK a year-and-a-half ago to join a steadily growing UCT radio astronomy group as an SKA SA fellow.

UCT researchers are leading four of the approved MeerKAT Key Science Projects, representing a quarter of MeerKAT time. One of these surveys is the 3 000-hour ThunderKAT survey for astrophysical transients.

Armstrong has been working on the design of this survey together with professor Rob Fender and associate professor Patrick Woudt, the leaders of the ThunderKAT project, which will search for all types of radio bursts and flashes in KAT-7 and MeerKAT data on timescales from seconds to years. Fender and Woudt are also Armstrong’s co-authors on the recently published paper.
“The publishing of this paper recognises a milestone for the SKA project; it is primarily a celebration for all the engineers and scientists who have worked hard to get KAT-7 to the point it is now,” notes Armstrong.

Another SKA boost

Following the signing of the RadioAstron space satellite agreement between the South African National Space Agency (SANSA) and the Russian Federal Space Agency (Roscosmos), at the 5th BRICS Summit, held in Durban this year, SANSA has announced it will be responsible for the installation, operations and maintenance of the receiving antennae.

According to Eugene Avenant, chief engineer at SANSA Space Operations, SANSA’s Space Operations ground station will undergo an equipment upgrade to accommodate the operational requirements to support the Russian RadioAstron orbiting space telescope.

The RadioAstron satellite was launched in July 2011 and carries a radio telescope that will obtain images and coordinates of various radio-emitting objects. As a single virtual telescope, it will be the world’s largest radio telescope, with a dish measuring approximately 390 000km. The mission has an expected lifetime of five years, and will support and improve investment in radio astronomy infrastructure in Africa and complement radio astronomy facilities such as the SKA.

SANSA’s role will include acting as a central point between Telkom – which has made an 18m C-Band antenna available for the RadioAston tracking and acquisition in SA – the Roscosmos system and the HartRAO.

Raoul Hodges, MD of SANSA Space Operations, explains the control of the ground-based equipment and data relayed from the spacecraft via TCP/IP connections will be combined in a router/switch at the Telkom Earth station and relayed to SANSA Space Operations via Fibre Optic connection.
“SANSA Space Operations will allocate a dedicated area with the required computer interfaces and apparatus to relay data to-and-from Roscosmos using terrestrial communication infrastructure,” says Hodges.