Abstract:
We demonstrate that polarimetric interferometry can be used to extractprecise spatial information about compact polarized flares of Sgr A*. Weshow that, for a faint dynamical component, a single interferometricbaseline suffices to determine both its polarization and projecteddisplacement from the quiescent intensity centroid. A second baselineenables two-dimensional reconstruction of the displacement, andadditional baselines can self-calibrate using the flare, enhancingsynthesis imaging of the quiescent emission. We apply this technique tosimulated 1.3 mm wavelength observations of a "hot spot" embedded in aradiatively inefficient accretion disk around Sgr A*. Our resultsindicate that, even with current sensitivities, polarimetricinterferometry with the Event Horizon Telescope can achieve ~5 μasrelative astrometry of compact flaring structures near Sgr A* ontimescales of minutes.