India, South Africa sizing up galaxies

Kolkata : India and South Africa have decided to expand their foot-print in the realm of stars underpinned by strong historical ties dating back to over 100 years. Bolstering 20 years of strategic partnership between both sides, India is participating in the multi-nation Square Kilometre Array (SKA) – set to become the world's most powerful radio telescope. SKA will be the premier radio astronomy facility once it's built, with stations located in Africa and Australia.

Unlike optical telescopes, which can be hampered by cloud or poor weather conditions on Earth, radio telescopes, working with signals at a longer wavelength, can be used even in cloudy skies. "Research areas that India and South Africa have been collaborating on include the study of transient events, developing new technology for optical and radio telescopes, and future research with the SKA," Steven M. Crawford, SALT Science Data Manager, South African Astronomical Observatory (SAAO), told IANS.

The Southern African Large Telescope (SALT) is the largest optical telescope in Southern Hemisphere and SAAO operates it on behalf of the SALT foundation, which includes South Africa, Inter University Centre for Astronomy and Astrophysics in Pune, India, and other international partners.

Crawford notes "it is a very exciting time for South Africa-India collaboration especially with how quickly both the communities are growing".
Radio astronomy via radio telescopes (a la Hollywood flick "Contact") provides alternative views to optical telescopes.

They can detect invisible gas and can reveal areas of space that may be obscured by cosmic dust. MeerKAT, a 64-dish precursor radio telescope to SKA, is currently being built in South Africa. MeerKAT's arsenal of 64 receptors will eventually be integrated into the SKA.

When fully up and running in the 2020s, SKA will have a contingent of at least 3,000 dishes spread across a square kilometre spanning two continents. There are a number of key science programmes that will be done on it and some of these involve South Africa and India partnerships.

Among these hot science projects is mapping hydrogen in the universe, informs Crawford, to trace the distribution of galaxies and matter in the universe. An international team of researchers led by N. Gupta and R. Srianand of Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune, will use MeerKAT in its first five years of operations to carry out the MeerKAT Absorption Line Survey (MALS) to trace the evolution of galaxies.

Hydrogen is the most abundant element in the universe and its building block as well. Stars essentially form from hydrogen. "Galaxies are made up of gas (hydrogen) and stars, and in order to understand how galaxies evolved, we need to understand how gas is converted to stars and vice versa.

To understand star formation, the key component of gas in galaxies is the cold gas component," Gupta told IANS. It is this gas component, which eventually collapses under gravity to form stars. "So if we map the distribution of the cold gas in galaxies, we can understand how galaxies had formed and evolved," Gupta said.

The MeerKAT telescope will start functioning at full capacity in 2018, but it is already generating data from its 16 to 32 dishes. Over five years, MALS will produce four petabyte (PB) of raw data and 12 PB of science data products i.e. images and spectra. "The main challenge is to deal with this large amount of data in terms of transfer from South Africa to IUCAA and then process it," Gupta explained.

However, there are opportunities for the Indian and South African software industry in this Big Data challenge. "Traditional methods of data processing will not scale to petabytes of data from next generation astronomy projects.

A close collaboration with SKA South Africa has been set up to deal with this challenge. For MALS, we are exploring new methods of data processing that lie at the crossroads of traditional astronomy, applied mathematics, and computer science technologies," he said. A radio astronomy data processing and archiving facility is being set-up at the IUCAA to automatically process and serve the data from MALS.

"Both the data processing facility and the big data solutions will be made publicly available to community." he said. Gupta said it's a win-win situation for both nations. "The telescopes are remembered for the discoveries they make and by setting up teams involving scientists across the world, the MeerKAT can be used to the best of its capacity."

By Sahana Ghosh