A study of the B and Be star population in the field of the LMC open cluster NGC2004 with VLT-FLAMES

Abstract

Observations of hot stars belonging to the young cluster LMC-NGC2004 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 (Halpha and Hgamma), [SII] and [NII] nebular lines. These lines are typical of HII regions. They could be associated with patchy nebulosities with a bi-modal distribution in radial velocity, with higher values (+335 kms^{-1}) preferentially seen inside the southern part of the known bubble LMC4 observed in HI at 21 cm.

12 pages, 17 figures, accepted to A&A

References in corpus (3)

• A New Look at the Large-Scale HI Structure of the LMC
• Pristine CNO abundances from Magellanic Cloud B stars I. The LMC cluster NGC 2004 with UVES
• Comparison of the H-alpha circumstellar disks in Be/X-ray binaries and Be stars

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• The VLT-FLAMES Tarantula Survey XVIII. Classifications and radial velocities of the B-type stars
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• Optical spectroscopy of 20 Be/X-ray Binaries in the Small Magellanic Cloud
• Early-type objects in NGC6611 and Eagle Nebula
• Classical Oe Stars in the Field of the Small Magellanic Cloud
• A Panchromatic Study of Massive Stars in the Extremely Metal-Poor Local Group Dwarf Galaxy Leo A
• Properties of the Be-type stars in 30 Doradus
• Stellar Inclination Angles from Be Star H$\alpha$ Emission-Line Profiles
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