First Results from MASIV: the Microarcsecond Scintillation-Induced Variability Survey

We report on the first results of the recent large-scale Micro-Arcsecond Scintillation Induced Variability (MASIV) 5 GHz VLA Survey of the northern sky. Our objective is to assemble a sample of 100-150 scintillating flat-spectrum extragalactic sources, which will be used to examine both the microarcsecond structure and parent populations of these sources, and to probe the turbulent interstellar medium responsible for the scintillation, One of the first findings of the MASIV Survey is that both the fraction of sources that scintillate, and their fractional scintillation amplitudes, are larger among the weaker, ∼100 mJy, sources.