Melbourne, April 3: An Indian PhD student living in Melbourne has settled one of astronomy’s burning questions with a radio telescope that she helped refurbish – detecting cosmic signals from outer space.

Hawthorn based, Manisha Caleb, 27, is enrolled at The Australian National University and works at Swinburne University, where she teamed up with her colleagues to detect three of the ‘fast radio bursts’ (FRBs) with the University of Sydney’s Molonglo radio telescope 40 km from Canberra.

Manisha has confirmed that mystery bursts of radio waves that astronomers have hunted for ten years now really do come from outer space.

“Because of the telescope’s characteristics, we’re 100 per cent sure the bursts came from space,” Manisha said talking to Bharat Times.

Manisha Caleb
Manisha Caleb refurbished telescope Molonglo

A Bachelor in Physics from Chennai, Manisha’s keen interest in Astro Physics led her to discover this ‘extraterrestrial signal’ to earth.

According to Manisha, this cosmic signal would have been “emitted some 6 billion years light years ago – that is even before there was any sign of life on earth”.

“The first FRB was discovered in 2007 and 4 more were discovered in 2013”, which is when Manisha began her research journey – revamping a telescope, Molonglo, “which operates at a frequency of 843MHz”.

The nature of the Molonglo telescope is such that operating at a lower frequency, unlike most dishes, Molonglo can see several spots or ‘beams’ on the sky at once.

So Koi Mil Gaya was not Bollywood fiction after all?

Although, Manisha is not aware of this Bollywood sci-fi, she was elated with her discovery.

“We were actually looking at a Megnetar (a type of star) – whether it emitted any radio signals… but when I woke up the next morning and checked the data, I was shocked.

“The data showed signals that came from miles away of the position of the Magnetar”. The bursts came from the direction of the constellations Puppis and Hydra.

While Manisha is not yet ready to call these signals as “life in outer-space”, she says these FRBs are pulsar signals that were emitted 6 billion light-years earlier.

Left to right Fabian Jankowski, Dave Temby, Sarah Bird, Duncan Campbell-Wilson, Chris Flynn, Manisha Caleb and Dick Hunstead, on site in June 2014 for the great RX box rollout.
Molonglo – on site near Canberra

In 2015 other mysterious radio signals were tracked down to a microwave oven at CSIRO’s Parkes radio telescope.

The researchers’ certainty of the ‘cosmic signals’, stem from the nature of the Molonglo telescope.

“Local radio interference shows up in several of Molonglo’s beams. Cosmic signals never show up in more than three. That’s how we knew these signals were cosmic,” said one of Manisha’s co-supervisors, Dr Chris Flynn of Swinburne University.

Dr Chris and Manisha have been part of a Swinburne-led team that has overhauled the telescope in the last two years, rebuilding it into a machine for hunting the mystery signals.

Swinburne’s Professor Matthew Bailes, who also supervises Manisha said that if this particular signal repeats, it would “give us a better chance to pin down its location and link it to a galaxy”.

The Molonglo telescope has a huge collecting area – 18,000 square metres and has a large field of view (eight square degrees on the sky), which makes it excellent for hunting for fast radio bursts.

Over the next two years the telescope will be improved even more, gaining the ability to localise bursts to within five arcseconds on the sky – an arcsecond being the width of a human hair when seen from ten metres away.

“Only one burst has ever been localised well enough to link it to a specific galaxy,” Manisha said.

“We expect Molonglo will do this for many more bursts.”

A paper on Manisha’s discovery has been accepted for publication in Monthly Notices of the Royal Astronomical Society.

With this extraordinary discovery under her belt, Manish will now take up her new job as a post-doctoral research fellow at the University of Manchester from June 2017.

Manisha is looking forward to researching FRBs with Telescope MeerKAT – operating at 1400 MHz, “a next generation path finder”.


feature image: (L to R) Fabian Jankowski, Dave Temby, Sarah Bird, Duncan Campbell-Wilson, Chris Flynn, Manisha Caleb and Dick Hunstead, on site in June 2014 for the great RX box rollout.

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