Special Astrophysics Seminar

Reconstructing complex pulsar scattering environments with global VLBI

Dana Simard

University of Toronto

Pulsar scintillation, the variation of the observed flux of a pulsar due to multi-path propagation, allows a glimpse into the small-scale plasma structures in the interstellar medium that scatter pulsar radiation - if we can infer their properties from the observed scintillation pattern. We have developed a model of scintillation from refractive plasma sheets that makes testable predictions which can be compared with observations to investigate these plasma structures. The main challenge in testing these models is mapping the scattered flux distribution of the pulsar on the sky, and to put physical scales to the constraints we must determine the scattering geometry of the system. I will discuss our novel interferometric technique to reconstruct the scattered flux of the pulsar and solve for the scattering geometry, even if the scattering environment is complex. This allows us to expand our study of pulsar scintillation to more systems and improve our global understanding of plasma scattering, which may benefit timing of millisecond pulsars and the aid in the interpretation of spectral structure in Fast Radio Bursts.