Presented by Southampton Theory Astrophysics and Gravity (STAG) Research Centre

Observing the unobservable: a multi-messenger view of black holes in the Event Horizon Telescope era

Black holes are one of the strangest byproducts of Einstein’s Theory of General Relativity: objects so compact that not even light can escape. However when they do manage to ‘harvest’ nearby material, they can channel this energy into several new forms that emit particles and radiation across the entire electromagnetic spectrum. Furthermore, the event horizon leads to a prediction that if we only had a good enough telescope, we should see a ring of light surrounding a dark ‘shadow’ indicating that point of no return.

In 2017 the Event Horizon Telescope (EHT), a planet sized array of radio telescopes, managed to resolve this feature for the solar system sized supermassive black hole in the M87 galaxy, and for the supermassive black hole in our own Milky Way, Sgr A*. After a brief overview of the key questions we have about black holes and their role in the Universe, Sera Markoff will put the ongoing EHT results into the context of our cutting edge understanding of black holes.

Sera Markoff is full professor of theoretical high-energy astrophysics and astroparticle physics at the University of Amsterdam, where she joined the faculty in 2006. Professor Markoff is an internationally recognised expert in compact object/black hole studies, ranging from the development of complex multi-messenger observations to modelling and interpretation. She is a founding member of the Event Horizon Telescope Collaboration (EHTC) and its Science Council, where she served most recently as Vicechair, and as of 2024 is member of its new Science Board, and co-coordinates the Multi-Wavelength Science WG. Her research, as well as her public outreach efforts, have been recognised by several prizes, including being named Fellow of the American Physical Society, the Dutch Research Council VIDI and VICI Personal Career Awards, the Willem de Graaff Prize for Public Outreach of the Royal Dutch Astronomical Society, an ERC Synergy Grant “Blackholistic” and Member of the Royal Netherlands Academy of Arts and Sciences. As part of the EHTC she also shared several other major prizes such as the Breakthrough Prize in Fundamental Physics, the Rossi Prize and the Einstein Medal.