Measurements of the Flux Densities, Positions and Angular Widths of Planetary Nebulae at 10 cm and 21 cm Wavelengths

摘要

Observations of 36 planetary and two diffuse nebulae have been made using the two 90-ft diameter antennas. The effects of confusion with non-thermal radio sources were examined statistically. In addition some indication of the nebulae for which confusion is most serious was obtained from a comparison of the radio positions with optical positions. Errors in the flux density measurements resulting from confusion should be small at 10 cm but are more serious at 21 cm. Angular widths of 29 of the nebulae were measured at 10 cm using spacings of 2351 and 4701 wavelengths east-west. The radio widths are in agreement with optical widths for approximately 80% of the nebulae, and in the remaining cases it appears probable that the discrepancies are an indication of confusion or of uncertainties in the optical data rather than non-thermal emission. The ratios of the measured radio and H beta flux densities of the nebulae show general agreement with the theoretical ratio for thermal emission, and discrepancies result most probably from errors in the estimated H beta absorption. (Author)