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

Abstract

The image of the emission surrounding the black hole in the center of the Milky Way is predicted to exhibit the imprint of general relativistic (GR) effects, including the existence of a shadow feature and a photon ring of diameter ~50 microarcseconds. Structure on these scales can be resolved by millimeter-wavelength very long baseline interferometry (VLBI). However, strong-field GR features of interest will be blurred at lambda >= 1.3 mm due to scattering by interstellar electrons. The scattering properties are well understood over most of the relevant range 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 mitigated by correcting the visibilities before reconstructing the image. This technique is also applicable to Sgr A* at longer wavelengths.

7 pages, accepted to ApJ

References in corpus (8)

• Event-horizon-scale structure in the supermassive black hole candidate at the Galactic Centre
• The Submillimeter Bump in Sgr A* from Relativistic MHD Simulations
• Simulating the Emission and Outflows from Accretion Disks
• Imaging the Supermassive Black Hole Shadow and Jet Base of M87 with the Event Horizon Telescope
• Jet-lag in Sgr A*: What size and timing measurements tell us about the central black hole in the Milky Way
• Discovery of Substructure in the Scatter-Broadened Image of Sgr A*
• Aperture Synthesis Observations of the Nearby Spiral NGC 6503: Modeling the Thin and Thick HI Disks
• Limits on the Position Wander of Sgr A*

Cited by in corpus (10)

• Black Holes in Modified Gravity (MOG)
• Imaging the Schwarzschild-radius-scale Structure of M87 with the Event Horizon Telescope using Sparse Modeling
• Super-resolution Full Polarimetric Imaging for Radio Interferometry with Sparse Modeling
• Radio observations of active galactic nuclei with mm-VLBI
• Testing General Relativity with Accretion-Flow Imaging of Sgr A*
• Dynamical Imaging with Interferometry
• The Effects of Accretion Flow Dynamics on the Black Hole Shadow of Sagittarius A${}^{\ast }$
• Stochastic Optics: A Scattering Mitigation Framework for Radio Interferometric Imaging
• MeqSilhouette : A mm-VLBI observation and signal corruption simulator
• No asymmetric outflows from Sagittarius A* during the pericenter passage of the gas cloud G2