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 journalArticlepeer-review

23 Scopus citations


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
Issue number2
StatePublished - Oct 20 2014


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

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Relative astrometry of compact flaring structures in Sgr A∗ with polarimetric very long baseline interferometry'. Together they form a unique fingerprint.

Cite this