Speaker: Hayley Bignall

Title: MASIV, VAST and the Ionised ISM

Abstract: The Micro-Arcsecond Scintillation-Induced Variability (MASIV) 5 GHz VLA Survey of 443 compact extragalactic radio sources found a strong correlation between 2-day variability amplitude and Hα emission measure along the line-of-sight. In addition, there was a correlation between Hα emission measure and characteristic timescale of variability. These results show that intraday variability is linked to the diffuse ionised gas in the Milky Way. The ASKAP VAST (Variables and Slow Transients) Survey Science Project will measure refractive interstellar scintillation of thousands of sources, tracing out stressed structures in the ionised interstellar medium over the southern hemisphere. I hope to initiate some discussion on what VAST, combined with other observations, will potentially tell us about the physics of the interstellar plasma.

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