Parkes observations for project P1015 semester 2019APRS_02

\r\nPulsar scintillation, variation of the observed pulsar flux against time and frequency, contains the information of light path difference between scattered light. Observations of scintillation from many bright pulsars suggest that the scattering is not random, but instead due to highly anisotropic scattering at one more thin lenses along the line of sight. The distance from the lens to the Earth can remain the same for years, and in some cases, the lens produces discrete images of the source that last for a month. The simplicity of the scattered images, and the longevity of the lenses suggest that it may be possible to model the lens with a finite number of parameters, and make a predictive model for pulsar scintillation. We propose to observe the scintillation of the brightest pulsar, B0833-45, which shows evidence of discrete lensed images and highly anisotropic scattering, with the Parkes Ultra Wideband Receiver and the H-OH receiver. With these observations, we will test scintillation models, which make concrete predictions for the frequency evolution of the scintillation pattern. We will also use the polarization data to search for magnetic spatial structures across the lens, which have been theorized as a mechanism to create the lenses responsible for anisotropic scattering. Meanwhile, we will use the great sensitivity and resolution of this giant interstellar lens to constrain the emission region size of the Vela pulsar.