50 picoarcsec astrometry of pulsar emission

@article{Pen201350PA,
  title={50 picoarcsec astrometry of pulsar emission},
  author={Ue-li Pen and Jean-Pierre Macquart and Adam T. Deller and Walter Brisken},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2013},
  volume={440}
}
We use VLBI imaging of the interstellar scattering speckle pattern associated with the pulsar PSR 0834+06 to measure the astrometric motion of its emission. The ~ 5AU interstellar baselines, provided by interference between speckles spanning the scattering disk, enable us to detect motions with sub nanoarcsecond accuracy. We measure a small pulse deflection of ~18+/-2 km (not including geometric uncertainties), which is 100 times smaller than the native resolution of this interstellar… 

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