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arXiv · 2212.01417

High Resolution VLBI Astrometry of pulsar scintillation screens with the $\theta-\theta$ Transform

Daniel Baker·Walter Brisken·Marten H. van Kerkwijk·Rik van Lieshout·Ue-Li Pen
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Abstract

The recent development of $\theta\mhyphen\theta$ techniques in pulsar scintillometry has opened the door for new high resolution imaging techniques of the scattering medium. By solving the phase retrieval problem and recovering the wavefield from a pulsar dynamic spectrum, the Doppler shift, time delay, and phase offset of individual images can be determined. However, the results of phase retrieval from a single dish are only known up to a constant phase rotation, which introduces extra parameters when doing astrometry using Very Long Baseline Interferometry. We present an extension to previous $\theta\mhyphen\theta$ methods using the interferometric visibilities between multiple stations to calibrate the wavefields. When applied to existing data for PSR B0834+06 we measure the effective screen distance and lens orientation with five times greater precision than previous works.

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Daniel Baker, Walter Brisken, Marten H. van Kerkwijk, Rik van Lieshout, Ue-Li Pen. 2022-12-02. High Resolution VLBI Astrometry of pulsar scintillation screens with the $\theta-\theta$ Transform. https://doi.org/10.1093/mnras%2Fstad2318

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