The Parkes 408 MHz Southern Survey

Extract

In recent years two 408 MHz surveys of the northern sky have been made to study the large-scale, low-surface-brightness features of the galactic background such as the loops and spurs (Haslam et al. 1970; Haslam et al. 1974). These surveys were designed to make maps down to the confusion limits of the telescopes used and to provide as far as practicable accurate calibration of the temperature scale and zero level for large-scale features. This work is complementary to the work of the large array telescopes; these telescopes can provide high resolution detail but they have lower surface brightness sensitivity, and have problems in determining the low-order terms which define the large-scale structure. The Parkes 408 MHz sourthern survey continues this work using the 64-m telescope to complete the coverage of the sky to the south pole. The project is a joint venture between the Max-Planck-Institut and CSIRO. For the southern survey it was felt desirable to measure the linear polarization distribution, besides making an accurate average temperature map in left-hand circular polarization (which is insensitive to variations of ionospheric Faraday effects). The previous surveys did not include linear polarization measurements.