Imaging an Event Horizon: Mitigation of Scattering toward Sagittarius A*

The image of the emission surrounding the black hole in the center ofthe Milky Way is predicted to exhibit the imprint of generalrelativistic (GR) effects, including the existence of a shadow featureand a photon ring of diameter ~50 μas. Structure on these scales canbe resolved by millimeter-wavelength very long baseline interferometry.However, strong-field GR features of interest will be blurred atλ >= 1.3 mm due to scattering by interstellar electrons. Thescattering properties are well understood over most of the relevantrange of baseline lengths, suggesting that the scattering may be(mostly) invertible. We simulate observations of a model image of Sgr A*and demonstrate that the effects of scattering can indeed be mitigatedby correcting the visibilities before reconstructing the image. Thistechnique is also applicable to Sgr A* at longer wavelengths.