Proper motion separation of Be star candidates in the Magellanic Clouds
  and the Milky Way
  We present a proper motion investigation of a sample of Be star candidates
towards the Magellanic Clouds, which has resulted in the identification of
separate populations, in the Galactic foreground and in the Magellanic
background. Be stars are broadly speaking B-type stars that have shown emission
lines in their spectra. In this work, we studied a sample of 2446 and 1019 Be
star candidates towards the LMC and SMC respectively, taken from the literature
and proposed as possible Be stars due to their variability behaviour in the
OGLE-II I band. JHKs magnitudes from the IRSF catalog and proper motions from
the SPM4 catalog, were obtained for 1188 and 619 LMC and SMC Be stars
candidates, respectively. Color-color and vector-point diagrams were used to
identify different populations among the Be star candidates. In the LMC sample,
two populations with distinctive infrared colours and kinematics were found,
the bluer sample is consistent with being in the LMC and the redder one with
belonging to the Milky Way disk. This settles the nature of the redder sample
which had been described in previous publications as a possible unknown
subclass of stars among the Be candidates in the LMC. In the SMC sample, a
similar but less evident result was obtained, since this apparent unknown
subclass was not seen in this galaxy. We confirm that in the selection of Be
stars by their variability, although generally successful, there is a higher
risk of contamination by Milky Way objects towards redder B$-$V and V$-$I
colors.
