The First Galaxy Cluster Discovered by the VISTA Variables in the V\'ia
  L\'actea Survey
  We report the first confirmed detection of the galaxy cluster
VVV-J144321-611754 at very low latitudes (l = 315.836$^{\circ}$, b =
-1.650$^{\circ}$) located in the tile d015 of the VISTA Variables in the V\'ia
L\'actea (VVV) survey. We defined the region of 30$\times$ 30 $arcmin^2$
centered in the brightest galaxy finding 25 galaxies. For these objects,
extinction-corrected median colors of (H - K$_{s}$) = 0.34 $\pm$ 0.05 mag, (J -
H) = 0.57 $\pm$ 0.08 mag and (J - K$_{s}$) = 0.87 $\pm$ 0.06 mag, and R$_{1/2}$
= 1.59 $\pm$ 0.16 $arcsec$; C = 3.01 $\pm$ 0.08; and Sersic index, n = 4.63
$\pm$ 0.39 were estimated. They were visually confirmed showing characteristics
of early-type galaxies in the near-IR images. An automatic clustering analysis
performed in the whole tile found that the concentration of galaxies
VVV-J144321-611754 is a real, compact concentration of early-type galaxies.
Assuming a typical galaxy cluster with low X-ray luminosity, the photometric
redshift of the brightest galaxy is $z = $ 0.196 $\pm$ 0.025. Follow-up near-IR
spectroscopy with FLAMINGOS-2 at the Gemini-South telescope revealed that the
two brighter cluster galaxies have typical spectra of early-type galaxies and
the estimated redshift for the brightest galaxy VVV-J144321.06-611753.9 is $z
=$ 0.234$\pm$0.022 and for VVV-J144319.02-611746.1 is $z =$ 0.232$\pm$0.019.
Finally, these galaxies clearly follow the cluster Red Sequence in the
rest-frame near-IR color--magnitude diagram with the slope similar to galaxy
cluster at redshift of 0.2. These results are consistent with the presence of a
bona fide galaxy cluster beyond the Milky Way disk.
