SALT aids in new discovery

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The Southern African Large Telescope in Sutherland helped detect the first white dwarf pulsar.
The Southern African Large Telescope in Sutherland helped detect the first white dwarf pulsar.

The Southern African Large Telescope (SALT) has helped detect the first white dwarf pulsar, the latest co-discovery that has astronomers eager to use the largest optical telescope in the southern hemisphere to unlock the galaxy's secrets.

Quick reaction times, as well as being significantly cheaper than similar European or American facilities in producing the science, are key competitive advantages, said a senior astronomer at the SALT consortium during a media visit.

"SALT is now living up to expectations, producing high-quality science data that probe the far reaches of the universe," said Ted Williams, a director at the South African Astronomical Observatory managing the site.

Scientists know of neutron stars: large objects about the size of the Sun that have compacted down at the end of their lives to something about 10km across, the last stop before a black hole.

Williams said these incredibly dense objects have been known for decades to produce pulsars, which emit regular pulses of radio waves and other electromagnetic radiation at rates of up to a thousand pulses per second.

"But there is another class of compact objects called white dwarfs, bigger, the size of the earth. So rather than 10 kilometres in size, we are looking at 6 000 kilometres and we've just discovered the very first white dwarf pulsar," he said of the previously unknown celestial phenomena.

Situated atop a hill in the desolate Northern Cape, about 365km north of Cape Town, the $43 million SALT telescope used its powerful spectroscopy light measurement tool to prove the existence of the white dwarf pulsar.

Shared by a consortium of partners from South Africa, India, North America and Europe, SALT's queuing system allows it to interrupt routine observations and within minutes focus its 10m optical telescope on new discoveries, said Williams.

In February, SALT was the first major telescope to take a spectrum of a supernova in the nearby Centaurus A galaxy hours after its discovery.

It also helped reveal one of the biggest explosions ever recorded in the universe, 200 times more powerful than a typical supernova and believed to have shone at 570 billion times the brightness of the Sun.

"It is what we wanted for South Africa and for Africa, not to stay at the margins but actually at the centre and beginning to do world-class quality work," said Naledi Pandor, minister of science and technology, who visited the telescope on Friday.

Together with Australia, SA is co-hosting the world's biggest and most advanced radio telescope, the $2 billion Square Kilometre Array, which will study the origins of the universe and help probe for extra-terrestrial life.

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