Description: | The upper panel shows rapid intensity variations in one of the water megamaser lines in the circumnuclear disk of galaxy NGC 3079, observed at a wavelength of 13.5mm with the GBT (Vlemmings, Bignall and Diamond, 2007, ApJ, 656, 198). The lower panel shows 16mm continuum observations of quasar PKS 1257-326 observed with the ATCA. The same mechanism, namely scintillation due to weak scattering in the nearby interstellar plasma of our own Galaxy, is proposed to explain the remarkably similar short-timescale intensity fluctuations seen in these completely different radio sources. (Any apparent correlation between the variability patterns is entirely a coincidence.) |