Event Horizon Telescope
When the South Pole Telescope and ALMA join the Event Horizon Telescope array, it will have a interferometric coverage that can image the black hole environment from several thousand Schwarzschild radii down to the horizon scale.
In preparation for these observations, we are running extensive time-dependent simulations of the low-density, radiatively inefficient accretion flow for many possible configurations of the black hole spin, viewing geometries, magnetic field configurations, and thermodynamics of the electrons in the flow. Using El Gato’s capabilities, we are able to track, for the first time, the variability in the flux and the image of the black hole at 1.3 mm, which is crucial for interpreting the observations correctly. The lightcurves below show two examples of predicted variability over 60 hours of densely sampled observations.
By comparing different simulations that have clear signatures of the bright photon ring or the footprints of possible jets, we assess the feasibility of the General Relativity tests that we will perform with these observations.