Variable structures in M87* from space, time and frequency resolved interferometry

Observing the dynamics of compact astrophysical objects provides insights into their inner workings, thereby probing physics under extreme conditions. The immediate vicinity an active supermassive black hole with its event horizon, photon ring, accretion disk, and relativistic jets is a perfect place to study general relativity magneto-hydrodynamics. observations M87* Very Long Baseline Interferometry (VLBI) by Event Horizon Telescope (EHT) allows investigate dynamical processes on time scales days. Compared regular radio interferometers, VLBI networks typically have fewer antennas low signal noise ratios (SNRs). Furthermore, source variable, prohibiting integration over improve SNR. Here, we present imaging algorithm that copes data scarcity temporal evolution, while providing uncertainty quantification. Our views task as Bayesian inference problem time-varying brightness, exploits correlation structure in time, reconstructs ${2+1+1}$ dimensional time-variable spectrally resolved image at once. We apply this method EHT observation validate our approach synthetic data. time- frequency-resolved reconstruction confirms variable structures emission ring. indicates extended outside ring itself.