Interplanetary Scintillations V. a Survey of the Northern Ecliptic

Abstract

view Abstract Citations (59) References (26) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Interplanetary Scintillations V. A Survey of the Northern Ecliptic Harris, Daniel E. ; Gundermann Hardebeck, Ellen Abstract Source structure on the scale 0'.' '.'5 was examined at the Arecibo Ionospheric Observatory by inter- planetary-scintillation observations of 5(x) Parkes and 4C sources. These sources were observed only when the angular distance to the Sun was between 10 and 20 . This assured the presence of detectable scintillations at 430 MHz for this scale. Slightly over half of all the sources displayed scintillations. For most of these, we were able to find rough values for the fraction of the source scintillating ( ) and upper limits to the diameter of the small component (4,). The results corroborate earlier deductions that most scintillating sources are complex, with at least one component being very small and containing a significant fraction of the total intensity. Because a large number of sources were examined, the occurrence of scintillations can be correlated with source intensity, source identification, and source spectra. The results indicate that: 1. There is no evidence for a statistical distance effect; that is, the scintillation index is not correlated with source intensity. However, the optically faint galaxies do scintillate more than the bright galaxies. 2. Three-quarters of the QSOs and one-half of the galaxies showed scintillation. 3. Most of the QSOs for which little or no scintillation was observed have normal or steep spectra. The strongly scintillating QSOs are more likely to have fiat or curved spectra. Publication: The Astrophysical Journal Supplement Series Pub Date: December 1969 DOI: 10.1086/190201 Bibcode: 1969ApJS...19..115H full text sources ADS | Related Materials (4) Part 1: 1967ApJ...147..433S Part 2: 1967ApJ...147..449C Part 3: 1969ApJ...155..645C Part 5: 1968AJS....73R..17H