RELATIVE ASTROMETRY OF COMPACT FLARING STRUCTURES IN Sgr A* WITH POLARIMETRIC VERY LONG BASELINE INTERFEROMETRY
Author(s)Johnson, Michael D.; Fish, Vincent L.; Broderick, Avery E.; Wardle, John F. C.; Marrone, Daniel P.; Doeleman, Sheperd Samuel; ... Show more Show less
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We demonstrate that polarimetric interferometry can be used to extract precise spatial information about compact polarized flares of Sgr A*. We show that, for a faint dynamical component, a single interferometric baseline suffices to determine both its polarization and projected displacement from the quiescent intensity centroid. A second baseline enables two-dimensional reconstruction of the displacement, and additional baselines can self-calibrate using the flare, enhancing synthesis imaging of the quiescent emission. We apply this technique to simulated 1.3 mm wavelength observations of a "hot spot" embedded in a radiatively inefficient accretion disk around Sgr A*. Our results indicate that, even with current sensitivities, polarimetric interferometry with the Event Horizon Telescope can achieve ~5 μas relative astrometry of compact flaring structures near Sgr A* on timescales of minutes.
Johnson, Michael D., Vincent L. Fish, Sheperd S. Doeleman, Avery E. Broderick, John F. C. Wardle, and Daniel P. Marrone. “RELATIVE ASTROMETRY OF COMPACT FLARING STRUCTURES IN Sgr A* WITH POLARIMETRIC VERY LONG BASELINE INTERFEROMETRY.” The Astrophysical Journal 794, no. 2 (October 6, 2014): 150. © 2014 The American Astronomical Society
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