Speaker
Description
Determining the origins of low-frequency (~MHz) variability of extragalactic sources has, until recently, largely been limited to small populations and/or single frequencies. Variability offers a unique opportunity to study both intrinsic properties of sources as well as the intervening media between source and observer. However, large population studies with significant spectral and temporal coverage have only recently become available with the development of radio telescopes like the Murchison Widefield Array (MWA). We have conducted a spectral variability survey of 15 sources over 72MHz to 10GHz using simultaneous observations with the MWA and the ATCA over a year. We will present the results of this survey which detects small scale structures (~mas scales) within AGN despite the low resolution of the ATCA and MWA (arcsecond to arcminute), confirmed with images using the LBA. In this talk we will discuss the power of spectral variability for determining morphologies and absorption mechanisms for compact peaked spectrum AGN which has been otherwise inconclusive.
