New telescope to throw light on evolution of universe

By March 2013, astronomers hope to catch a glimpse of an early phase of the universe, 100-500 million years after the Big Bang thanks to a telescope being developed as an international venture.

It will help generate panoramic images of sky at different frequencies, which will aid researchers get information about the universe at different times during its evolution.
The Raman Research Institute (RRI) is participating in this project, along with Harvard University, Massachusetts Institute of Technology from the US, and a consortium of Australian universities, led by Curtin University, to develop Murchison Wide field Array (MWA), a radio telescope.

It is being built in Murchison shire in Western Australia, which is approximately 50,000 sq km in area, but has a population of only 500. Hence, it is a radio-quiet zone and a safe haven for observing radio waves emitted by celestial sources.

The telescope will enter its operational phase by March 2013. The MWA is a radically new type of radio telescope with no moving parts. It is dependent on prodigious computer power to create wide-field images of the radio sky, which is somewhat similar to panoramic photography. RRI scientists built the digital receivers for the project, which began in 2006.

“The RRI designed, developed and tested the digital receivers for the telescope, and they have now been transported to the site location. The digital receivers convert the radio signals emitted from the radio sky and picked by 128 antennae, spread over a circular area with a radius of about 1.5 km, to a digital format and feed them to computers for further processing.

“The computers are programmed to take panoramic images of the sky at different frequencies. From these images, astronomers deduce information about the universe at different times in its evolution,” said Prof N Udaya Shankar, Astronomy and Physics Group, RRI.

“Till now, the telescope was in the engineering phase and is now making a transition into the science phase. We are expecting the first light from the cluster of 128 antennae by March 2013. A first analysis of these images is expected demonstrate the exceptional potential of MWA, “ he added.

According to Shankar, one of the main reasons for getting a good glimpse of a universe, when it is just 100 million years young after the Big Bang, is to get an idea of how the universe came into being. This is a very important phase in the evolution of universe, because the first luminous objects were born during this period.

“These objects radiated energy and knocked electrons from neutral H atoms and the universe went from being neutral to being ionised plasma,” Shankar said. He said that using the MWA telescope they will try to find out how and when did ionization happened, what were the properties of the first luminous objects formed in the universe.

However, Shankar felt that getting concrete answers would take at least a year. “Seeing the universe in this phase is very challenging since it is like looking for a needle in a haystack. No wonder that about 1,000 hours of observation will be required before astronomers start getting answers to some of these questions. No doubt exciting times are ahead in this field,” Shankar added.