New H2O masers in Seyfert and FIR bright galaxies. III. The Southern
  Sample
  Recently, a relationship between the water maser detection rate and far
infrared (FIR) flux densities has been established as a result of two 22 GHz
maser surveys in a complete sample of galaxies (Dec>-30 degree) with 100 micron
flux densities of > 50 Jy and > 30 Jy. This survey has been extended to the
southern galaxies in order to discover new maser sources and to investigate the
galaxies hosting the maser spots with particular emphasis on their nuclear
regions. A sample of 12 galaxies with Dec<-30 degree and S(100 micron)>50 Jy
was observed with the 70-m telescope of the Canberra Deep Space Communication
Complex (CDSCC) at Tidbinbilla (Australia) in a search for water maser
emission. The average 3 sigma noise level of the survey is 15 mJy for a 0.42
km/s channel, corresponding to a detection threshold of ~0.1 solar luminosities
for the isotropic maser luminosity at a distance of 25 Mpc. Two new detections
are reported: a kilomaser with an isotropic luminosity L_H2O ~5 solar
luminosities in NGC3620 and a maser with about twice this luminosity in the
merger system NGC3256. The detections have been followed-up through continuum
and spectral line interferometric observations with the Australia Telescope
Compact Array (ATCA). In NGC3256, a fraction (about a third) of the maser
emission arises from two hot spots associated with star formation activity,
which are offset from the galactic nuclei of the system. The remaining emission
may arise from weaker centers of maser activity distributed over the central 50
arcsec. [abridged]
