Orateur
Description
Radio waves emitted by pulsars experience a frequency-dependence propagation effect caused by free elections in the ionized interstellar medium (IISM), parameterized by the dispersion measure (DM). Temporal variations in the DM of pulsars provide a powerful probe of the density fluctuations of the free electrons in the ionized interstellar medium. These variations provide insight into the turbulent and large-scale overdensities in the IISM in dynamic environments, such as supernova remnants and pulsar wind nebulae.
In this presentation, I will present the measurements of DM variations of 364 young pulsars measured at the Parkes radio telescope. By combining more than 15 years of observations with the Multibeam receiver and the recently installed ultrawideband receiver, which allows for simultaneous measurements across 3.4 GHz of bandwidth and an increase in the DM measurement precision of an order of magnitude. We are able to measure significant DM variations for more than 83 pulsars. We characterize these variations using a power-law wavenumber spectrum and find good agreement with a Kolmogorov scaling along different lines of sight. I will also highlight several pulsars that show deviations from this behaviour and discuss possible physical explanations.