Massive open star clusters using the VVV survey III: A young massive
  cluster at the far edge of the Galactic bar
  Context: Young massive clusters are key to map the Milky Way's structure, and
near-IR large area sky surveys have contributed strongly to the discovery of
new obscured massive stellar clusters.
  Aims: We present the third article in a series of papers focused on young and
massive clusters discovered in the VVV survey. This article is dedicated to the
physical characterization of VVV CL086, using part of its OB-stellar
population.
  Methods: We physically characterized the cluster using $JHK_S$ near-infrared
photometry from ESO public survey VVV images, using the VVV-SkZ pipeline, and
near-infrared $K$-band spectroscopy, following the methodology presented in the
first article of the series.
  Results: Individual distances for two observed stars indicate that the
cluster is located at the far edge of the Galactic bar. These stars, which are
probable cluster members from the statistically field-star decontaminated CMD,
have spectral types between O9 and B0V. According to our analysis, this young
cluster ($1.0$ Myr $<$ age $< 5.0$ Myr) is located at a distance of
$11^{+5}_{-6}$ kpc, and we estimate a lower limit for the cluster total mass of
$(2.8^{+1.6}_{-1.4})\cdot10^3 {M}_{\odot}$. It is likely that the cluster
contains even earlier and more massive stars.
