We have described SEST observations to search for mm-bright southern radio sources. Combined with source samples in the southern equatorial region (Tornikoski et al. 1996), this sample provides a useful first list of sources for making southern hemisphere pointing observations for single dish telescopes. As noted earlier, the noise level appears to be dominated by spatial and temporal atmospheric fluctuations; the planned replacement of the present SEST chopper wheel system with a nutating subreflector may improve the sensitivity of the telescope for continuum observations.
In the longer term, a large sample of calibration sources with
mean separations of only a few degrees will be important for
phase-calibration of the proposed southern millimeter
interferometers (Woody et al. 1995; Holdaway et al.
1994). At present four southern mm interferometers are under
development: the NRAO Millimeter
Array
, the European Large
Southern Array LSA (Booth 1992, 1996), the Japanese LMSA
(Ishiguro et al. 1994), and the mm upgrade of the Australia
Telescope Compact Array. Site-testing of various locations in the Chilean
Atacama Desert is underway for the first three (latitude 
S). We
note that our survey has identified one pair of bright (approximately 1Jy
at 3mm) sources with separation of only 2
, i.e. 
. This pair could be used for making further on-site
test observations of phase-calibration methods over angular separations of a
few degrees using a single-baseline interferometer with relatively small
antennas.
From an astrophysical point of view our sample adds to the list of
blazars with detected strong millimeter emission. These sources can be
added to existing monitoring programs to improve statistics about flux
and spectral variability amongst different classes of beamed sources
(Tornikoski et al. 1993). We have identified a
number of sources which are circumpolar from southern sites and can be
observed continuously in search of intra-day variability (Wagner &
Witzel 1995) at millimeter wavelengths. As described in Sect. 4, a
number of the detected sources show evidence for significant foreground
column densities either within the host galaxies or elsewhere along the
line of sight; these should be searched for centimeter and millimeter
absorption lines. Additionally four of our detected sources lie within
10 degrees of the galactic plane (
, 
,
and 
) and can be used to search for cold
molecular gas within our galaxy (Liszt 1994).
Acknowledgements
We thank the SEST staff for their assistance during our observing. The SEST is operated jointly by ESO and the Swedish National Facility for Radio Astronomy, Onsala Space Observatory, Chalmers University of Technology. We would like to thank Drs. Mike Kesteven, Miller Goss, and Niven Tasker for their assistance during the early stages of this project. This research has made use of the NASA/IPAC Extragalactic Database which is operated by the Jet Propulsion Laboratory, Caltech with the National Aeronautics and Space Administration.