MEERKAT TELESCOPE LAUNCH: Snapshot of centre of the Milky Way reveals clearest ever image of supermassive black hole
In the months and years to come, the data used to build a picture of the centre of the Milky Way will be analysed and academic papers written, as astronomers work at answering some of our galaxy’s deeper secrets.
Fernando Camilo knew he had a kick-ass picture when he found everyone talking about it at the printing shop. “I went to the store to pick up the banner, several people from that store in Cape Town were like saying, ‘What is this? This is amazing’,” recalls Camilo, chief scientist at the South African Radio Astronomy Observatory. Camilo and his colleagues had realised that with the launch of the MeerKat telescope coming up, they had to show the world, the gathered politicians and media something special. The idea was to take a snapshot of the centre of the Milky Way galaxy. It had been done before, but no one had got it quite right. The spot is difficult to capture; there are clouds of gas and dust in the way that obscure it from ordinary telescopes. “This is a really hard region of the galaxy to image. From a technical perspective it is super hard because you have a combination of bright structures and very faint features. And you have some features that are very large and some are very fine. And with the combination of all that, unless your telescope is awesome it makes it incredibly hard to make images of it,” explains Camilo. This image would be constructed from radio signals captured by 64 dishes, in the remote Karoo, from a patch of space 25,000 light years away. Usually, Camilo explains, these kinds of images take a while to capture, and require a lot of tinkering with the telescope. But the engineers felt confident it could be pulled off right away, even though MeerKat had only months earlier gone on line. In June 2018, MeerKat’s 64 dishes got it – the clearest ever image of a supermassive black hole bang in the middle of the Milky Way. It is this image Camilo had printed on that 4m x 2.5m banner that was revealed to the world on Friday. But this is not just a pretty picture, it has a science value too. Captured in that frame are mysterious magnetised filaments that are only found in this part of the Milky Way. They have been a mystery since they were discovered in 1980. In the months and years to come, Camilo says the data used to build that picture of the centre of the Milky Way will be analysed and academic papers written, as astronomers work at answering some of our galaxy’s deeper secrets. “They’ve built an instrument that will be the envy of astronomers everywhere and will be in great demand for years to come,” says Farhad Yusef-Zadeh of Northwestern University, in the US, who is an expert on those filament structures. Scientists have been working on observations from MeerKat since April. “They have received some data that they are super excited about, but we asked those teams not to release their images until we had this presidential inauguration of the telescope,” says Camilo. For the next six years MeerKat is going to hold the title of being the largest and most sensitive radio telescope in the southern hemisphere; that is, until the Square Kilometre Array comes on line. But the MeerKat is likely only to be completed in the 2050s and could be in use for a long time. “We are looking at a 50-year lifespan of the project, but if you look at these telescopes they function way above that. You are probably looking at a good 100 years,” says Lorenzo Raynard, head of communications for the South African Radio Astronomy Observatory. Over the coming years, telescopes from eight other countries across Africa will be joining MeerKat and, with these added “ears” pointed to the sky, astronomers will be getting even better resolutions of deep space. But with a long lifespan will come challenges. This spasely populated part of the Karoo was chosen because of its limited Radio Frequency Interference (RFI). “Humans just give off a large volume of RFI,” says Raynard. The instruments on the telescope are so sensitive that a passing satellite overhead can produce unwanted radio interference. A nearby cellphone can destroy equipment and in the future, it is likely that radio signal pollution will increase as technology advances and populations even in the sparely populated Karoo grow. Raynard, however, believes that government and legislation will protect the project in the future. Already the local population in the area is having to learn to live with these restrictions, even though before the arrival of the telescopes cellphone reception at best was patchy. Scientists have been tasked with providing connectivity for the population, using alternative technologies. One of these is a low frequency trunk radio system that has been set up, for farmers and the municipalities to use. And there are also expected to be technological spin-offs from MeerKat, that will eventually filter down to other scientific disciplines. The analysis and collection of Big Data, is likely to be one of these. MeerKat receives and processes huge amounts of data every second. Being able to handle such large volumes of data could assist in some unusual applications. “You are building an instrument that will improve peoples' lives. With big data, physicians will be able to do diagnosis more quickly. Another spin-off, we have seen more recently, is that instead of people monitoring the ocean line to spot sharks you can use electronic monitoring of the ocean and determine what marine life is there. So you can identify the threat much quicker,” explains Raynard. That’s the future but for the moment, Camilo is still dealing with the response to that kick ass picture. “I received overnight 20 emails from scientists around the world, and they asking 'Can I have the data for that image?' And we are saying there is a process, and that involves South Africa.” DM