2020-11-27 11:00  P5A-1

The First Images of a Black Hole and General Relativistic Magnetohydrodynamic Accretion/Jet: achievements and challenges

Hung-Yi Pu

On April 10th, 2019, the Event Horizon Telescope (EHT) collaboration, a global very-long-baseline interferometry (VLBI) network of radio telescopes, reported the first images of a black hole: horizon-scale images of the compact and jetted radio source at the core of the elliptical galaxy M87. The observed ring-like structure is broadly consistent with the black hole shadow features expected from a spinning Kerr black hole with 6.5 billion solar mass, and the asymmetric ring feature implies that the black hole spin vector is pointed away from Earth, provided that the black hole spin and M87's large scale jet are aligned. These interpretations are obtained with the help of  the state-of-the-art frameworks of general relativistic magnetohydrodynamics (GRMHD), including black hole accretion and jet formation processes. The talk will focus on the achievements and challenges of modeling black hole shadow images at the radio frequencies.