The Gaia-ESO Survey: Catalogue of H$\alpha$ emission stars
  We discuss the properties of H$\alpha$ emission stars across the sample of
22035 spectra from the Gaia-ESO Survey internal data release, observed with the
GIRAFFE instrument and largely belonging to stars in young open clusters.
Automated fits using two independent Gaussian profiles and a third component
that accounts for the nebular emission allow us to discern distinct
morphological types of H$\alpha$ line profiles with the introduction of a
simplified classification scheme. All in all we find 3765 stars with intrinsic
emission and sort their spectra into eight distinct morphological categories:
single--component emission, emission blend, sharp emission peaks, double
emission, P-Cygni, inverted P-Cygni, self--absorption, and emission in
absorption. We have more than one observation for 1430 stars in our sample,
thus allowing a quantitative discussion of the degree of variability of
H$\alpha$ emission profiles, which is expected for young, active objects. We
present a catalogue of stars with properties of their H$\alpha$ emission line
profiles, morphological classification, analysis of variability with time and
the supplementary information from the SIMBAD, VizieR, and ADS databases. The
records in SIMBAD indicate the presence of H$\alpha$ emission for roughly 25%
of all stars in our catalogue, while at least 305 of them have already been
more thoroughly investigated according to the references in ADS. The most
frequently identified morphological categories in our sample of spectra are
emission blend (23%), emission in absorption (22%), and self--absorption (16%).
Objects with repeated observations demonstrate that our classification into
discrete categories is generally stable through time, but categories P-Cygni
and self--absorption seem less stable, which is the consequence of discrete
classification rules, as well as of the fundamental change in profile shape.
