At low metallicity, B-type stars show lower loss of mass and, therefore,
angular momentum so that it is expected that there are more Be stars in the
Magellanic Clouds than in the Milky Way. However, till now, searches for Be
stars were only performed in a very small number of open clusters in the
Magellanic Clouds. Using the ESO/WFI in its slitless spectroscopic mode, we
performed a Halpha survey of the Large and Small Magellanic Cloud. Eight
million low-resolution spectra centered on Halpha were obtained. For their
automatic analysis, we developed the ALBUM code. Here, we present the
observations, the method to exploit the data and first results for 84 open
clusters in the SMC. In particular, cross-correlating our catalogs with OGLE
positional and photometric data, we classified more than 4000 stars and were
able to find the B and Be stars in them. We show the evolution of the rates of
Be stars as functions of area density, metallicity, spectral type, and age.Comment: talk at IAUS25
