Relative astrometry of compact flaring structures in Sgr A∗ with polarimetric very long baseline interferometry

Michael D. Johnson, Vincent L. Fish, Sheperd S. Doeleman, Avery E. Broderick, John F C Wardle, Daniel P Marrone

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

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.

Original languageEnglish (US)
Article number150
JournalAstrophysical Journal
Volume794
Issue number2
DOIs
StatePublished - Oct 20 2014

Fingerprint

astrometry
very long baseline interferometry
interferometry
flares
event horizon
accretion disks
centroids
hot spot
polarization
accretion
telescopes
wavelength
timescale
sensitivity
synthesis
wavelengths
flaring

Keywords

  • black hole physics
  • Galaxy: center
  • submillimeter: general
  • techniques: high angular resolution
  • techniques: interferometric
  • techniques: polarimetric

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Relative astrometry of compact flaring structures in Sgr A∗ with polarimetric very long baseline interferometry. / Johnson, Michael D.; Fish, Vincent L.; Doeleman, Sheperd S.; Broderick, Avery E.; Wardle, John F C; Marrone, Daniel P.

In: Astrophysical Journal, Vol. 794, No. 2, 150, 20.10.2014.

Research output: Contribution to journalArticle

Johnson, Michael D. ; Fish, Vincent L. ; Doeleman, Sheperd S. ; Broderick, Avery E. ; Wardle, John F C ; Marrone, Daniel P. / Relative astrometry of compact flaring structures in Sgr A∗ with polarimetric very long baseline interferometry. In: Astrophysical Journal. 2014 ; Vol. 794, No. 2.
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