Massive open star clusters using the VVV survey IV. WR 62-2, a new very
  massive star in the core of the VVV CL041 cluster
  Context The ESO Public Survey VISTA Variables in the V\'ia L\'actea (VVV)
provides deep multi-epoch infrared observations for an unprecedented 562 sq.
degrees of the Galactic bulge and adjacent regions of the disk. Nearly 150 new
open clusters and cluster candidates have been discovered in this survey. Aims
We present the fourth article in a series of papers focussed on young and
massive clusters discovered in the VVV survey. This article is dedicated to the
cluster VVV CL041, which contains a new very massive star candidate, WR 62-2.
Methods Following the methodology presented in the first paper of the series,
wide-field, deep JHKs VVV observations, combined with new infrared
spectroscopy, are employed to constrain fundamental parameters (distance,
reddening, mass, age) of VVV CL041. Results We confirm that the cluster VVV
CL041 is a young (less than 4 Myrs) and massive (3 +/- 2 x 10^3 Msol) cluster,
and not a simple asterism. It is located at a distance of 4.2 +/- 0.9 kpc, and
its reddening is A_V = 8.0 +/- 0.2 mag, which is slightly lower than the
average for the young clusters towards the centre of the Galaxy. Spectral
analysis shows that the most luminous star of the cluster, of the WN8h spectral
type, is a candidate to have an initial mass larger than 100 Msol.
