Observations of the Effective Linear Polarization of Discrete Radio Sources at 21.2 CM Wavelength.

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Observations of the Effective Linear Polarization of Discrete Radio Sources at 21.2 CM Wavelength. Bologna, J. M. ; McClain, E. F. ; Rose, W. K. ; Sloanaker, R. M. Abstract The effective linear polarizatioi~ of 90 discrete radio sources has been determined at 21.2-cm wavelength from measurements made with the National Radio Astronomy Observatory, 300-ft diameter, transit reflector during May and June 1963. Simultaneous measurements of antenna temperature were made at orthogonal polarizations with two identical radiometers connected to orthogonal, linearly polarized outputs of a circularwaveguide feed antenna mounted at the focus. The feed antenna could be rotated about its axis througb 340 deg. Except for the source CTA 102 (Harris, D. E., and Roberts, J. A., Publ. Astron. Soc. Pacific 72, 237, 1960), the sources were selected from the 3C catalogues (Edge, D. 0., Shakeshaft, J. K., Mc- Adam, W. B., Baldwin, J. E., and Archer, S., Mem. Roy. Astron. Soc. 68, 37,1959; Bennett, A. S., Mem. Roy. Astron. Soc. 68, 1963, 1962). The measured degree of linear polarization was less than 1 % for about one-fourth of the sources, and ranged from 1% to 9.0% for the rest of the sources, with a mean estimated standard measurement error of about 1%. When the degree of polarization of the radio sources is plotted against galactic latitude or sine of the galactic latitude there is a strong indication that the degree of polarization increases away from the galactic plane. In most cases the sources used for this correlation are stated by others to be extragalactic or probably extragalactic. A complete catalogue of sources will be published in the near future. Between 50 and 60 additional sources are available using the NRAO 300-ft instrument and it is expected measurements will be made on these additional sources during the latter half of 1964. Publication: The Astronomical Journal Pub Date: 1964 DOI: 10.1086/109485 Bibcode: 1964AJ.....69S.533B full text sources ADS |