RADIO ASTRONOMY RESEARCH: UNISA graduate seeks to map Southern Hemisphere skies in more detail

AUGUST 12, 2014

A University of South Africa (Unisa) graduate at the College of Science, Engineering and Technology has embarked on an innovative research project that will strengthen the view of the southern hemisphere sky using a technique known as Very  Long Baseline Interferometry (VLBI).

Sayan Basu, who is currently a Radio Astronomy researcher at Hartebeesthoek Radio Astronomy Observatory (HartRAO), is completing his PhD in Radio Astronomy at Unisa’s College of Graduate Studies. His research will use VLBI as a powerful technique in radio astronomy linking together widely separated radio telescopes, to build a more detailed picture of the universe in the southern hemisphere.

“VLBI is known for imaging distant cosmic radio sources, spacecraft tracking, and for applications in astrometry. With radio dishes that are effectively as large as entire countries, astronomers can peer into black holes, map the surfaces of stars, perform earth rotation studies, and even track the drift of continents,” explains Basu.

How VLBI works is that two or more radio telescopes from different places observe an extragalactic radio source at the same time. By observing the same source this technique can measure the distance between these antennas with an accuracy of a few millimetres.

Basu says there are limited facilities/ radio telescopes that participate in VLBI observing sessions in southern hemisphere. “There is only the Hartebeesthoek Radio Astronomy Observatory (HartRAO) 26m radio telescope which takes part in VLBI observations for the southern hemisphere. As a result, there are far more detailed observations of the northern hemisphere sky available and considerable work needs to be done to reach the same level of detail for the southern hemisphere.”

This research project will bring together various telescopes and reference sources to densify the images in the southern hemisphere sky including:

  • The Celestial Reference Frame Deep South (CRDS) - an international campaign that runs VLBI sessions with telescopes in the southern hemisphere
  • VLBI sessions from Australia through the Long Baseline Array (LBA) Calibrator Survey (LCS)
  • Pioneer instruments from southern hemisphere like the South African MeerKAT radio telescope and the Square Kilometre Array (SKA) can also perform VLBI

Basu was selected to represent Unisa and South Africa at the 8th International VLBI Service for Geodesy and Astrometry (IVS) General Meeting in China which he attended with five other participants from HartRAO in March 2014. The research project was embraced by other senior researchers and members of the IVS board and received serious attention from Chopo Ma, a senior scientist of NASA Goddard Space Flight Centre.

The meeting empowered Basu to gain support from other universities whose collaborations are vital to the Radio Astronomy research.

“Alessandra Bertarini from Max Planck Institute for Radio Astronomy is one of the collaborators we are excited to be working with,” says Basu. “We hope to considerably progress our research as we build a more detailed picture of the universe in the southern hemisphere.”

Unisa’s Science Campus provides the ideal framework for cutting-edge scientific research with world-class infrastructure, facilities and support to explore new frontiers of science on the African continent.

“The development of the campus represented a major investment by the university in the development of science and research,” says Professor Mandla Makhanya, Unisa Principal and Vice Chancellor.

“It is an environment which meets the educational and training needs of its distance learning Science students, something not usually associated with Open Distance and eLearning institutions. The research Sayan Basu is completing will make a major contribution to radio astronomy research. We’re proud of the advances he is making as he completes his PhD through Unisa.”


Photo caption: Some of the radio telescopes at Hartebeesthoek Radio Astronomy Observatory. Photo courtesy of Credit: M Gaylard / HartRAO.