Physical modelling of radiative emissions from regions on event horizon-scales

Wednesday 22 Jul 2026, 14:00 → 15:00 Asia/Shanghai

Tsung-Dao Lee Institute/S4F-SW - Open Area (Tsung-Dao Lee Institute)

Ziri Younsi

Host: Yosuke Mizuno
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Meeting ID: 201504070 (no password)

Abstract: 
In 2019 the first image of a black hole was published by the Event Horizon Telescope, showcasing event horizon-scale structure of the M87 central region. In 2022, the EHT then published the first image of the black hole in the heart of our Milky Way, Sagittarius A*. Whilst the image morphologies are similar, highlighting that the regime of strong-field gravity is important, these regions are also correlated with transient phenomena which can be observed across the electromagnetic spectrum and beyond. In this talk I will explain how we are able to model the radiative emissions from these systems in both general relativity and other theories of gravity. I will discuss some of the theoretical and modelling approaches used to build physics-guided models of these complex, dynamical, and strongly curved regions. I will then outline the potential of event horizon-scale images of black holes to facilitate studies of microphysical processes and gravity.

Bio:
Ziri Younsi is a Lecturer at University College London. He obtained a Ph.D. from University College London in 2014. He was a postdoctoral fellow in the Black Hole Camera project at Goethe University Frankfurt, Alexander von Humboldt Fellow at Goethe University Frankfurt, Leverhulme Trust Early Career Research Fellow at UCL, and UKRI Stephen Hawking Fellow at UCL. His research utilizes multi-frequency polarized radiation transport to create physically accurate models of compact object environments, enabling scientific interpretation of observational data. He is an active member of the EHT, next-generation EHT, and LISA projects.