A study of the B and Be star population in the field of the LMC open cluster NGC 2004 with VLT-FLAMES

Observations of hot stars belonging to the young cluster LMC-NGC 2004 and its surrounding region have been obtained with the VLT-GIRAFFE facilities in MEDUSA mode. 25 Be stars were discovered; the proportion of Be stars compared to B-type stars is found to be of the same order in the LMC and in the Galaxy fields. 23 hot stars were discovered as spectroscopic binaries (SB1 and SB2), 5 of these are found to be eclipsing systems from the MACHO database, with periods of a few days. About 75% of the spectra in our sample are polluted by hydrogen (Hα and Hγ), [ion{S}{ii}] and [ion{N}{ii}] nebular lines. These lines are typical of ion{H}{ii} regions. They could be associated with patchy nebulosities with a bi-modal distribution in radial velocity, with higher values (+335 km s^-1) preferentially seen inside the southern part of the known bubble LMC4 observed in ion{H}{i} at 21 cm.