Revolutionary times: How MeerKAT and Earth-sized telescopes are expanding our thinking

Posted on October 11, 2018

There was global excitement when MeerKAT, the biggest radio telescope in the world, was launched in Carnarvon in the Northern Cape in July. But few people could have been as excited as Professor Roger Deane, who heads up the University of Pretoria’s radio astronomy research team in the Department of Physics.

“MeerKAT will revolutionise our understanding of gravitational waves and how galaxies evolve,” Prof Deane says. “It’s been designed to be able to go after some of the big questions in contemporary astrophysics, making it an even more exciting time to be an astronomer in South Africa.”

MeerKAT is made up of a total of 64 antennas, each 13.5 metres in size, and placed across eight kilometres of the vast Karoo. While it is 100% South African owned, MeerKAT is a precursor to the Square Kilometre Array (SKA), which will be a global instrument made up of telescopes located across Africa and in Australia. Once established, SKA will become the biggest scientific infrastructure on the planet.

“The fact that South Africa won the bid for the SKA highlights the country’s exceptional engineering and scientific capabilities, as well as the impact of sustained, high-level political support for science mega-projects of this nature,” Prof Deane says.

                                                       Prof Roger Deane

Of course, Prof Deane and his colleagues also personally celebrated MeerKAT’s launch, as it brings great advancements to their efforts to position the University of Pretoria as a leading site of radio astronomy research on the African continent and in the world.  The UP astronomy group plans to use MeerKAT as a standalone instrument, as well as the major node for a network of antennas across the planet – essentially creating a telescope that will be the size of the Earth.              

“Having the use of an Earth-sized telescope will particularly benefit my research focus: supermassive black holes,” Prof Deane says. “Supermassive black holes are the largest types of black holes, found at the centre of galaxies. They are regions of space with such strong gravitational effects that not even light can escape from within them. By synthesising a planet-sized telescope, we will be able to pinpoint and zoom into black holes in the universe with much greater precision.”

Prof Deane is particularly interested in two applications of this technique. For starters, he is part of an international team working on making the first image of a black hole shadow, using the Event Horizon Telescope (EHT). The EHT is a network of antennas across four continents, in extreme locations like the South Pole and an Hawaiian volcano summit, to provide the sharpest view of the universe – about 1000 times better than the Hubble Space Telescope. The second application is the search for closely orbiting pairs of black holes, a seemingly rare phenomenon at this point. “Supermassive black hole pairs that get really close to one another produce gravitational waves – the squeezing and stretching of space-time first predicted by Einstein a century ago,” Prof Deane says. “We want to use this global array of telescopes to measure how rare this phenomenon really is, because understanding that will help us understand the gravitational wave signal that MeerKAT aims to detect in a completely different type of experiment.”

The UP astronomy group is also focused on using MeerKAT to better understand the evolution of galaxies, specifically the cold gas that serves as the fuel for star formation. “Immediately following the Big Bang, there were no stars or galaxies, however, today we observe a rich cosmic tapestry of galaxies all around us. As astronomers, we are trying to understand all the evolutionary stages of galaxies and black holes from the Big Bang to present day,” Prof Deane says. “Because of the extreme sensitivity of the MeerKAT telescope, we’ll be able to see much deeper than before for certain types of observations. Furthermore, as an additional sensitivity boost, our team uses a special technique called strong gravitational lensing, which enables much deeper observations of the universe towards special directions in the sky.”

                                                                            Image: Galactic centre

Prof Deane is working hard to develop the department’s research capacity to carry out world-leading science on MeerKAT, the SKA, and the EHT. One necessity in doing so is being able to process large volumes of data efficiently with machine-learning techniques, which requires close cross-faculty collaboration. “Doing so will help train the data-savvy astronomers that will do the science with MeerKAT and the SKA. We have a strong undergraduate programme, which is one of the largest in the country, so I am highly energised by UP’s potential to build a large group of postgraduate students and researchers.” 

One of the keys to achieving this is to ensure astronomers have suitably powerful processing capabilities, with software solutions designed to handle astronomy-specific problems. To meet this challenge, UP has partnered with the Universities of Cape Town and the Western Cape to create the Inter-University Institute for Data Intensive Astronomy (IDIA). IDIA has been set up to process “astronomically big data” – data on a scale not previously encountered in the case of the SKA.

For Prof Deane and the young astronomy group being built up at UP, there’s a great deal of inspiration in the air. “There has been no better time to be an astronomer in South Africa. The largest big data scientific facility is right in our back yard, along with an unbound potential for revolutionary discoveries.”

- Author Louise de Bruin

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