Speaker: Associate Prof Roger Deane - University of Pretoria, SA
On 10 April 2019, the Event Horizon Telescope Collaboration revealed the first image of a black hole. This required a large international effort by over 200 scientists spread across five continents. The team uses a technique called radio interferometry, synthesising a virtual telescope with the effective diameter of the Earth - a technique known as Very Long Baseline Interferometry (VLBI). By using antennas with separations on inter-continental scales, and observing a wavelength of light of 1 mm, the team is able to achieve an effective angular resolution of ~20 micro-arcseconds (the apparent size of a doughnut on the moon). Apart from providing visual confirmation of the existence of black holes, the size and shape of the shadow feature could in future provide a stringent test of Einstein’s General Theory of Relativity in the strong-field regime. In this DARA e-seminar, I will provide an overview of the instrument and the key scientific results, as well as looking to the future of this exciting field, including the possible expansion of the array onto African soil.