Image Processing for the Sydney University Molonglo Sky Survey (SUMSS)

The Sydney University Molonglo Sky Survey (SUMSS) is a deep radio survey at 843MHz, covering the region south of -30° declination. Designed to be a southern counterpart of the northern NRAO VLA Sky Survey (NVSS), SUMSS is over 40% complete, and it is now time to devise ways to generate the source catalogue for the survey. We describe here new methods to deal with image artifacts to minimise spurious fits by automatic source fitting algorithms. With the new techniques, an automatically generated, objective catalogue can be made to a 10mJy cutoff. Catalogues can be made to a 5mJy cutoff provided that special care is taken and certain artifacts are avoided.