Thursday 13/06/2019 @ 11:30, Sala IV piano Battiferro
Roger Deane (Rhodes University), "Imaging Black Hole Shadows with the Event Horizon Telescope"
On 10 April 2019, the Event Horizon Telescope (EHT) Collaboration revealed the first image of a black hole shadow. This required a large international effort from over 200 scientists spread across five continents, using a global very long baseline interferometric array observing at a wavelength of 1.3 mm. The instrument achieves an angular resolution of ~20 ?as and resolves the central compact radio source in M87 into a bright emission ring with a diameter of 42 ± 3 ?as. This image not only provides strong visual evidence of the existence of supermassive black holes, but also that they are the central engines of active galactic nuclei. The EHT is clearly a new tool to explore gravity in its most extreme limit and on a mass scale that was so far not accessible. In the pursuit of this goal, the EHT has developed a wide range of tools that will very useful to VLBI and radio astronomy in general. In this talk, I will provide an overview of the instrument, the techniques developed to achieve its scientific objectives, discuss a few of the key inferences from these first results, and look to the future of this exciting field.