General relativistic radiation transport: Implications for VLBI/EHT
  observations of AGN discs, winds and jets
  In 2019, the Event Horizon Telescope Collaboration (EHTC) has published the
first image of a supermassive black hole (SMBH) obtained via the Very Large
Baseline Interferometry (VLBI) technique. In the future, it is expected that
additional and more sensitive VLBI observations will be pursued for other
nearby Active Galactic Nuclei (AGN), and it is therefore important to
understand which possible features can be expected in such images. In this
paper, we post-process General Relativistic Magneto-Hydrodynamical (GR-MHD)
simulations which include resistivity, thus providing a self-consistent jet
formation model, including resistive mass loading of a wind launched from a
disc in Keplerian rotation. The ray-tracing is done using the General
Relativistic Ray-Tracing code GRTRANS assuming synchrotron emission. We study
the appearance of the black hole environment including the accretion disc,
winds and jets under a large range of condition, varying black hole mass,
accretion rate, spin, inclination angle, disc parameters and observed
frequency. When we adopt M87-like parameters, we show that we can reproduce a
ring-like feature (similar as observed by the EHT) for some of our simulations.
The latter suggests that such Keplerian disc models thus could be consistent
with the observed results. Depending on their masses, accretion rates, spin and
the sensitivity of the observation, we note that other SMBHs may show
additional features like winds and jets in the observations.
