On the influence of the Sun on the rapid variability of compact extragalactic sources
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
2 Urumqi Observatory, the National Astronomical Observatories, the Chinese Academy of Sciences, Urumqi 830011, PR China
Received: 30 October 2010
Accepted: 16 March 2011
Since December 2004, we have performed a program to monitor intraday variable sources at a frequency of 5 GHz at the Urumqi Observatory. We present our analysis of the variability characteristics of the flat-spectrum radio source AO 0235+164, which detects an annual cycle in the variability amplitude. This appears to correlate with the solar elongation of the source. A thorough analysis of the results of the MASIV IDV survey – which provides the variability characteristics of a large sample of compact radio sources – confirms that there is a small but detectable component of the observed fractional modulation that increases with decreasing solar elongation. We discuss the hypothesis that the phenomenon is related to interplanetary scintillation.
Key words: scattering / quasars: individual: AO 0235+164 / radio continuum: general / solar wind / surveys
© ESO, 2011