The East-West Structure of Radio Sources at 1425 MHz

Citation

Fomalont, Edward Berel (1967) The East-West Structure of Radio Sources at 1425 MHz. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/W9HN-MY72. https://resolver.caltech.edu/CaltechETD:etd-04302008-153110

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The east-west radio structures of 532 sources have been obtained with the Caltech variable spacing interferometer at a frequency of 1425 MHz. The visibility functions, measured at nine interferometer spacings between 144[...] and 2626[...], are presented in tabular form for all of the sources. The east-west source structures were calculated by a model fit of the data or by a direct numerical inversion of the data. The statistics of the radio structures have been analyzed. There are three major structure types: simple double, halo-core and triple. The simple double sources have two distinct components of emission having nearly equal intensities and diameters with the radio galaxy lying at the center of the two components in most cases. The halo-core sources consist of a small radio core, usually complex, coincident with the radio galaxy and a much larger region of emission, the halo, not necessarily symmetrically disposed around the radio core. The triple and more complex sources are discussed briefly and it is suggested that many are genetically related to double and halo-core sources. Other results from the observations are: a slight correlation of the radio and optical structure of galaxies; a difference for the N-S relationship of quasars and radio galaxies based on their statistical separation by brightness temperature; a model for the evolution of a double source in which the component separation increases at five times the rate of the expansion of the component diameters; the lack of simple sources characterized by one main region of emission; and the suggestion that 3C120 and 3C236 are involved in a violent explosion.

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