Astrophysics Seminar

The ionised interstellar medium (IISM) is a dynamic medium that plays an important role in the transport of energy in a galaxy. The IISM is observable through its imprints of propagation effects on radio waves, such as dispersion, angular scattering and scintillation. It is mainly through pulsar scintillation that the turbulence in the IISM was infered, but the picture of a volume-filling turbulent IISM is currently undergoing revision. There is mounting evidence now for scattering to arise in structures that are highly localized along the line of sight. Scintillation of pulsars has been a powerful tool to probe the structure of the IISM, and somewhat unconventional observational and analysis methods have broken new ground. For example, very long baseline interferometry, high-resolution spectroscopy, simultaneous multi-station observations and novel algorithmic approaches are providing new insights in this direction, that have come to be known collectively as a discipline called scintillometry. I will describe some recent work and shed light on the future avenues, and conclude with the big questions that confront scintillometry.