SIMBAD references

Relative proper motions (PMs) and cluster membership probabilities (Pµ) were derived for ∼ 2500 stars in the field of the open star cluster NGC 3766. The cluster was observed in the B and V broad-band filters at two epochs separated by ∼ 6 yr using a wide-field imager mounted on the WFI@ESO 2.2-m telescope. All CCD frames were reduced using the astrometric techniques described by Anderson et al. The PM rms error for stars brighter than V ∼ 15mag is 2.0masyr-1, but it gradually increases up to ∼ 4masyr-1 at V ∼ 20mag. Using PM data, membership probabilities were derived for the stars in the region of the cluster. They indicate that one Ap and three Be stars are members of the cluster. A reddening of E(B - V) = 0.22±0.05mag, a distance of 2.5±0.5kpc and an age of ∼ 20Myr were derived using stars with Pµ > 70 per cent. A mass function slope of x = 1.60±0.10 was derived for the cluster, and the cluster was found to be dynamically relaxed. Finally, we provide positions, calibrated B and V magnitudes, relative PMs and membership probabilities for the stars in the field of NGC 3766. We have produced a catalogue that is electronically available to the astronomical community.