The GALAH survey: a catalogue of carbon-enhanced stars and CEMP
  candidates
  Swan bands - characteristic molecular absorption features of the C$_2$
molecule - are a spectroscopic signature of carbon-enhanced stars. They can
also be used to identify carbon-enhanced metal-poor (CEMP) stars. The GALAH
(GALactic Archaeology with Hermes) is a magnitude-limited survey of stars
producing high-resolution, high signal-to-noise spectra. We used 627,708 GALAH
spectra to search for carbon-enhanced stars with a supervised and unsupervised
classification algorithm, relying on the imprint of the Swan bands. We
identified 918 carbon-enhanced stars, including 12 already described in the
literature. An unbiased selection function of the GALAH survey allows us to
perform a population study of carbon-enhanced stars. Most of them are giants,
out of which we find 28 CEMP candidates. A large fraction of our
carbon-enhanced stars with repeated observations show variation in radial
velocity, hinting that there is a large fraction of variables among them. 32 of
the detected stars also show strong Lithium enhancement in their spectra.
