A Survey of the Local Group of Galaxies for Symbiotic Binary Stars. I.
  First detection of symbiotic stars in M33
  We present and discuss initial selection criteria and first results in M33
from a systematic search for extragalactic symbiotic stars. We show that the
presence of diffuse interstellar gas emission can significantly contaminate the
spectra of symbiotic star candidates. This important effect forces upon us a
more stringent working definition of an extragalactic symbiotic star. We report
the first detections and spectroscopic characterisation of 12 symbiotic
binaries in M33. We found that four of our systems contain carbon-rich giants.
In another two of them the giant seems to be a Zr-enhanced MS star, while the
remaining six objects host M-type giants. The high number ratio of C to M
giants in these binaries is consistent with the low metallicity of M33. The
spatial and radial velocity distributions of these new symbiotic binaries are
consistent with a wide range of progenitor star ages.
