S Africa’s MeerKAT radio telescope proves its mettle, observes exotic star activity

6th April 2018 By: Marleny Arnoldi - Creamer Media Online Writer

S Africa’s MeerKAT radio telescope proves its mettle, observes exotic star activity

MeerKAT antennas in the Northern Cape

Foremost astronomy and astrophysics research publication, the Astrophysical Journal (ApJ), on Friday published a study of a magnetar that awoke in 2017 from a three-year slumber, which was observed by South Africa’s MeerKAT radio telescope, which is being built in the Northern Cape.

ApJ reported that a magnetar is a star that is one of the most magnetic objects known in the universe and that the MeerKAT telescope triggered observations by the National Aeronautics and Space Administration’s (Nasa’s) X-ray telescopes that were orbiting Earth.

This observation marks the first publication in scientific literature of astronomical discoveries requiring the use of MeerKAT, which heralds its arrival into the stable of world-class research instruments. The article, titled Revival of the magnetar PSR J1622-4950: observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra and NuSTAR, has 208 authors.

South African Radio Astronomy Observatory (Sarao) chief scientist Dr Fernando Camilo explained that the observation started on April 26, 2017, while monitoring the long-dormant magnetar with the Commonwealth Scientific and Industrial Research Organisation’s Parkes radio telescope, in Australia.  

“A colleague noticed that the telescope was emitting bright radio pulses every four seconds, but a few days later, Parkes underwent a planned month-long maintenance shutdown,” he noted, adding that the team then started monitoring with the MeerKAT telescope.

Although the MeerKAT is still under construction, with no more than 16 of its eventual 64 radio dishes available, the commissioning team started regular monitoring of the magnetar 30 000 light years from Earth.

“The MeerKAT observations proved critical to make sense of the few X-ray photons we captured with Nasa’s orbiting telescopes – for the first time, X-ray pulses have been detected from this star, every four seconds,” said Camilo.

Put together, the observations reported on Friday help scientists better develop a picture of the behaviour of matter in “unbelievably extreme physical conditions,” unlike any that can be experienced on Earth.

Moreover, Camilo pointed out that a handful of the 208 authors that wrote the article on this observation are astronomers that are specializing in the study of magnetars and related stars.

The majority of authors belong to the “MeerKAT builders list”, which includes many engineers and scientists from the SKA South Africa project (a Sarao project) and commercial enterprises in South Africa, that have been developing and building the MeerKAT over the last decade.

The MeerKAT is a project of the South African Department of Science and Technology.

“MeerKAT is an enormously complex machine. To make the exquisitely sensitive images of the radio sky – that will also enable scientists to better understand how galaxies such as the Milky Way have formed and evolved over the history of the universe – the 64 MeerKAT antennas generate data at enormous rates,” stated MeerKAT programme manager Thomas Abbott.

These 64 antennas, each 13.5 m in diameter, are distributed across a span of 8 km in a remote area of the Northern Cape. The official unveiling of the telescope is planned for the second half of this year.

SKA director-general Professor Phil Diamond enthused that “the MeerKAT will eventually be integrated into Phase 1 of the SKA mid-telescope, bringing the total dishes at the SKA project’s disposal to 197, creating the most powerful radio telescope in the world.”