PKS 0405-385 flux-density monitoring

Such a behaviour suggests a nearby (<30pc away) scattering screen along the line of sight to these radio sources. While quasars PKS 1257-326 and J1819+385 scintillate continuously over several years of monitoring, PKS 0405-385 shows episodes of strong scintillations which last only a few months.

Here, I present the results of flux-density monitoring of PKS 0405-385 over 6yr at four Stokes parameters and four frequencies. Two explanations of the episodic behaviour of interstellar scintillation in this source are discussed; morphological evolution of the source and changes in the properties of the interstellar medium along the line of sight.