Structure of 194 Southern Declination Radio Sources from Interplanetary Scintillations

Abstract

Interplanetary scintillation observations of 194 southern declination radio sources have been made at 327 MHz. The angular size and the fraction of the flux present in the scintillating component have been estimated. More than half of the observed sources scintillate and contain ;;;'10% of their flux in angular size smaller than 0"·5. About 75 % of the quasars and '" 50 % of the galaxies and the blank field objects scintillate. For quasars the spectral index seems to be correlated with the strength of scintillation; most of the flat spectrum quasars are strong scintillators and are unresolved. The scintillating properties of blank field objects are consistent with Bolton's hypothesis that most of these are galaxies beyond the plate limit of the Sky Survey.