Research on the observational appearance of black holes, both in general relativity and
modified gravity, has been in full swing since the Event Horizon Telescope Collaboration …

Magnetic fields regulate black hole (BH) accretion, governing both the inflow and outflow
dynamics. When a BH becomes saturated with large-scale vertical magnetic flux, it enters a …

Black hole (Bh) X-ray binaries cycle through different spectral states of accretion over the
course of months to years. Although persistent changes in the Bh mass accretion rate are …

The conventional accretion disk lore is that magnetized turbulence is the principal angular
momentum transport process that drives accretion. However, when dynamically important …

We discuss applications of the study of the new and barely explored class of changing-look
(CL) narrow-line Seyfert 1 (NLS1) galaxies and comment on their detection with the space …

The extremes of Active Galactic Nuclei (AGN) variability offer valuable new insights into the
drivers and physics of AGN. We discuss some of the most extreme cases of AGN variability; …

Accretion physics studies the process of gravitational capture of ambient matter by massive
stars. The background processes are very challenging to observe and measure due to the …

We carry out idealized three-dimensional general-relativistic magnetohydrodynamic
simulations of prograde, weakly magnetized, and geometrically thick accretion flows where …

Changing-look active galactic nuclei (CLAGNs) are characterized by extreme variations in
line emission over short time-scales, mostly affecting broad H lines. While a few hundred …

General relativistic magnetohydrodynamic (GRMHD) simulations of black hole tilted disks—
where the angular momentum of the accretion flow at large distances is misaligned with …