WUNA Lunch Talk:

Michael Johnson

University of California, Santa Barbara

Imaging Pulsar Polar Caps with Nyquist-Limited Scintillation Statistics

December 12

12:10PM, Room 230, NRAO, Edgemont Road


For pulsars observed at decimeter wavelengths, the interstellar scattering material acts as an AU-scale, stochastic lens, which permits nanoarcsecond resolution. However, uncovering this information is challenging: the pulsar emission is noiselike, as are the rapidly-evolving scattering kernel and the additive background. I will discuss our recent work to fully characterize these statistics, opening a new window into the pulsar's magnetosphere and enabling the recovery of information from highly scattered and dispersed sources. In particular, the limiting regime of Nyquist-limited resolution offers a particularly elegant representation and interpretation. I will demonstrate these techniques using GBT observations of the Vela pulsar, for which we achieved a spatial resolution of 4 km at the pulsar, or roughly 100 picoarcseconds, and will discuss further improvements via interferometry and RadioAstron.