Jan 27, 2021

Speaker: Oliver Porth (University of Amsterdam)

Title: Black holes and friends: accretion and jet formation around compact objects

Abstract: Over the last two decades, general relativistic magnetohydrodynamic simulations (GRMHD) have drawn a robust broad-brush picture of black hole accretion and jet formation in low-luminosity sources. The observations by the Event Horizon Telescope and the GRAVITY interferometers now probe accretion physics with unprecedented detail requiring equally sophisticated dynamical models. I will take this opportunity to review the state-of-the-art in 3D numerical source models and showcase recent results obtained with the Black Hole Accretion Code. To investigate variability and flares, we have analyzed distinct dynamical features like flux tubes orbiting in the accretion flow and plasmoid chains forming in the black hole magnetosphere. I will also report results from simulations of accretion onto ''black hole mimickers'' like Boson stars. A comparison to resolved EHT and GRAVITY data is now constraining on these models allowing new tests of strong field gravity, accretion and jet dynamics.