Imaging an event horizon: Mitigation of scattering toward Sagittarius a

Vincent L. Fish; Michael D. Johnson; Ru Sen Lu; Sheperd S. Doeleman; Katherine L. Bouman; Daniel Zoran; William T. Freeman; Dimitrios Psaltis; Ramesh Narayan; Victor Pankratius; Avery E. Broderick; Carl R. Gwinn; Laura E. Vertatschitsch

doi:10.1088/0004-637X/795/2/134

Imaging an event horizon: Mitigation of scattering toward Sagittarius a

Vincent L. Fish, Michael D. Johnson, Ru Sen Lu, Sheperd S. Doeleman, Katherine L. Bouman, Daniel Zoran, William T. Freeman, Dimitrios Psaltis, Ramesh Narayan, Victor Pankratius, Avery E. Broderick, Carl R. Gwinn, Laura E. Vertatschitsch

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68 Scopus citations

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 μas. Structure on these scales can be resolved by millimeter-wavelength very long baseline interferometry. However, strong-field GR features of interest will be blurred at λ ≥ 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.

Original language	English (US)
Article number	134
Journal	Astrophysical Journal
Volume	795
Issue number	2
DOIs	https://doi.org/10.1088/0004-637X/795/2/134
State	Published - Nov 10 2014

Keywords

Galaxy: center
galaxies: individual (Sgr A∗)
scattering
techniques: image processing
techniques: interferometric

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1088/0004-637X/795/2/134

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title = "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 μas. Structure on these scales can be resolved by millimeter-wavelength very long baseline interferometry. However, strong-field GR features of interest will be blurred at λ ≥ 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.",

keywords = "Galaxy: center, galaxies: individual (Sgr A∗), scattering, techniques: image processing, techniques: interferometric",

author = "Fish, {Vincent L.} and Johnson, {Michael D.} and Lu, {Ru Sen} and Doeleman, {Sheperd S.} and Bouman, {Katherine L.} and Daniel Zoran and Freeman, {William T.} and Dimitrios Psaltis and Ramesh Narayan and Victor Pankratius and Broderick, {Avery E.} and Gwinn, {Carl R.} and Vertatschitsch, {Laura E.}",

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doi = "10.1088/0004-637X/795/2/134",

language = "English (US)",

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T2 - Mitigation of scattering toward Sagittarius a

AU - Fish, Vincent L.

AU - Johnson, Michael D.

AU - Lu, Ru Sen

AU - Doeleman, Sheperd S.

AU - Bouman, Katherine L.

AU - Zoran, Daniel

AU - Freeman, William T.

AU - Psaltis, Dimitrios

AU - Narayan, Ramesh

AU - Pankratius, Victor

AU - Broderick, Avery E.

AU - Gwinn, Carl R.

AU - Vertatschitsch, Laura E.

PY - 2014/11/10

Y1 - 2014/11/10

N2 - 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 μas. Structure on these scales can be resolved by millimeter-wavelength very long baseline interferometry. However, strong-field GR features of interest will be blurred at λ ≥ 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.

AB - 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 μas. Structure on these scales can be resolved by millimeter-wavelength very long baseline interferometry. However, strong-field GR features of interest will be blurred at λ ≥ 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.

KW - Galaxy: center

KW - galaxies: individual (Sgr A∗)

KW - scattering

KW - techniques: image processing

KW - techniques: interferometric

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JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

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ER -

Imaging an event horizon: Mitigation of scattering toward Sagittarius a

Abstract

Keywords

ASJC Scopus subject areas

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