Indian astronomers help get peek into ancient cosmos
Stars born billions of years ago emit signals, and a specialised radio telescope can capture such signals. Indian astronomers have been part of an international team building such radio telescopes to increase our knowledge of the early universe.
Four astronomers of the Raman Research Institute (RRI) in Bangalore participated in building a new radio telescope in Australia to track and receive signals from distant stars and galaxies, which emerged at cosmic dawn, 13 billion years ago.
"We participated in building the Murchison Widefield Array (MWA) radio telescope in Western Australia outback to unfold the cosmic history that remained a mystery so far," RRI director Ravi Subrahmanyan told IANS.
Unlike an optical telescope through which planets, stars and galaxies are "viewed" and studied from the earth, a radio telescope uses antennas, which operate in the radio frequency of the electromagnetic spectrum to detect "signals" emitted by celestial bodies and objects in the outer space for studying their phenomena.
"The primary goal of the radio telescope is to 'view' the birth of the first stars and galaxies - the cosmic dawn - almost 13 billion years ago. The telescope entered the operational phase July 9 to get a deep insight into cosmic phenomena," Subrahmanyan said.
Besides Subrahmanyan and three other astrophysicists - Uday Shankar, K.S. Dwaraknath and A.A. Deshpande - four top engineers from the institute also partnered with counterparts from Australia, New Zealand and the US in building the mammoth radio telescope to enable astronomers to glean insights into the Milky Way and galaxies beyond, pulsing and exploding stellar objects.
"We have designed and built the digital receivers of the telescope at the institute, installed and commissioned them to also study the influence of the sun on interplanetary space weather close to the earth," Subrahmanyan said.
The digital receivers pick signals from the antennas and perform complex algorithms to process the data for transmitting it to a central processing unit, which computes the imaging information. The MWA will survey the entire southern sky and make sensitive images of targetted regions.
The data will provide astronomers insights into the dramatic evolution of the primordial cosmic gas that led to the formation of the first stars and galaxies in the early universe. As a joint initiative of Australia, India, New Zealand and the US, the MWA consists of 2,048 wideband antennas optimised to operate in 80-330MHz frequency.
The antennas are arranged as 128 square tiles, each of which has 16 pairs of receivers spread across 3 km at the Murchison Radio-astronomy Observatory, about 200 km from the Western Australian coast and 700 km north of Perth.
The MWA will image the inter-galactic hydrogen gas surrounding early galaxies during the cosmological epoch of re-ionisation, and study the structure of the gas in the Milky Way galaxy and its magnetic field. The first observing cycle is underway and indications are the telescope and data are meeting the expectations set during commissioning.
"The telescope has begun gathering the weak radio signals from deep space that will be analysed over the coming years by scientists at RRI and in the US and Australia using parallel computing systems," institute spokesman Ram Subramaniyan told IANS.
The MWA is a precursor to the international Square Kilometre Array (SKA), a global project to be built as the world's largest radio telescope across Australia and South Africa.
"This next-generation radio telescope (SKA) will herald path-breaking advances in the deployment of distributed and parallel antenna technology, integrated receivers, energy systems, communications and computing," Subramaniyan pointed out.
According to Australian Nobel Laureate Brian Schmidt, who participated in the project, the MWA is a momentous step towards setting up the SKA low-frequency telescope nearby over the next five years. Schmidt was a joint winner of the Nobel Prize for Physics in 2011 for proving that the universe is expanding at an accelerating rate.