http://arxiv.org/abs/1605.05727
We carried out observations of pulsar PSR B1919+21 at 324 MHz to study the distribution of interstellar plasma in the direction of this pulsar. We used the RadioAstron (RA) space radiotelescope together with two ground telescopes: Westerbork (WB) and Green Bank (GB). The maximum baseline projection for the space-ground interferometer was 60000 km. We show that interstellar scintillation of this pulsar consists of two components: diffractive scintillations from inhomogeneities in a layer of turbulent plasma at a distance $z_{1} = 440$ pc from the observer; and weak scintillations from a screen located near the observer at $z_{2} = 0.13$ pc. Furthermore, in the direction to the pulsar we detected a prism that deflects radiation, leading to a shift of observed source position. We show that the influence of the ionosphere can be ignored for the space-ground baseline. Analysis of the spatial coherence function for the space-ground baseline (RA-GB) yielded the scattering angle in the observer plane: $\theta_{scat}$ = 0.7 mas. An analysis of the time-frequency correlation function for weak scintillations yielded the angle of refraction in the direction to the pulsar: $\theta_{ref, 0}$ = 120 ms and the distance to the prism $z_{prism} \leq 1.3$ pc.
V. Shishov, T. Smirnova, C. Gwinn, et. al.
Fri, 20 May 16
18/55
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