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1st of March 2023
ATNF Colloquium
Scintillation Arcs: Scattering Screens and Surprises
Robert Main (MPIfR)
Abstract: Radio emission from pulsars scintillates in time and frequency – an interference pattern arising from small-scale inhomogeneities in electron density in the interstellar medium. The discovery of "scintillation arcs" showed that scintillation is often remarkably ordered, well described by scattering in highly anisotropic thin screens. Scintillation arcs are a powerful probe of small-scale structures in the ionized interstellar medium, and can be used to determine the location of screens, measure the variable time delays from scattering, and measure pulsar orbits on the plane of the sky. In this talk, I will show the first scintillation results from the Thousand Pulsar Array at MeerKAT, with scintillation arcs seen in upwards of 100 pulsars. I will then describe a long-term multi-frequency study of the high-velocity pulsar B1508+55 with LOFAR and Effelsberg, solving the observed scintillation from two interacting screens, and where low frequency `echoes' preceded a change in scintillation by ~3 years. Motivated by this study, I will describe ongoing efforts to connect scintillation across many scales in frequency, and the most promising future avenues.

The image above shows scintillation arcs towards >100 pulsars observed as part of the MeerKAT Thousand Pulsar Array.

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