First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole

Understand

We present measurements of the properties of the central radio source in M87 using Event Horizon Telescope data obtained during the 2017 campaign.

• We develop and fit geometric crescent models (asymmetric rings with interior brightness depressions) using two independent sampling algorithms that consider distinct representations of the visibility data.
• We show that the crescent family of models is statistically preferred over other comparably complex geometric models that we explore.
• We calibrate the geometric model parameters using general relativistic magnetohydrodynamic (GRMHD) models of the emission region and estimate physical properties of the source.