
%0 Journal Article
%A Cim&ograve;, Giuseppe 
%A Beckert, T. 
%A Krichbaum, T. P. 
%A Fuhrmann, L. 
%A Kraus, A. 
%A Witzel, A. 
%A Zensus, J. A. 
%T A Very Rapid Extreme Scattering Event in the IDV Source 0954+658
%J Publications of the Astronomical Society of Australia
%D 2002/06/28
%V 19
%N 1
%P 10-13
%K quasars: individual (0954+658) &#8212; ISM: structure
%R https://doi.org/10.1071/AS01097
%U https://www.publish.csiro.au/paper/AS01097 
%X Extreme scattering events (ESEs) are dramatic variations of the flux density at gigahertz frequencies caused by ray path distortions within an isolated inhomogeneity (&#8216;plasma lens&#8217;) in the interstellar medium. These events are characterised by a deep flux density minimum in the light curve with, in some cases, surrounding maxima. The variability time scales range from weeks to months. These phenomena show a strong frequency dependence, in which the variability amplitudes increase with wavelength. During an intraday variability (IDV) monitoring project (March 2000), a feature resembling an ESE-like event appeared in the variable light curve of 0954+658, however with a time scale of less than two days. We will discuss this effect and its implications for a better description of the interstellar medium. 
