New variable stars discovered in the fields of three Galactic open
  clusters using the VVV Survey
  This project is a massive near-infrared (NIR) search for variable stars in
highly reddened and obscured open cluster (OC) fields projected on regions of
the Galactic bulge and disk. The search is performed using photometric NIR data
in the $J$-, $H$- and $K_s$- bands obtained from the Vista Variables in the
V\'ia L\'actea (VVV) Survey. We performed in each cluster field a variability
search using Stetson's variability statistics to select the variable
candidates. Later, those candidates were subjected to a frequency analysis
using the Generalized Lomb-Scargle and the Phase Dispersion Minimization
algorithms. The number of independent observations range between 63 and 73. The
newly discovered variables in this study, 157 in total in three different known
OCs, are classified based on their light curve shapes, periods, amplitudes and
their location in the corresponding color-magnitude $(J-K_s,K_s)$ and
color-color $(H-K_s,J-H)$ diagrams. We found 5 possible Cepheid stars which,
based on the period-luminosity relation, are very likely type II Cepheids
located behind the bulge. Among the newly discovered variables, there are
eclipsing binaries, $\delta$ Scuti, as well as background RR Lyrae stars. Using
the new version of the Wilson & Devinney code as well as the "Physics Of
Eclipsing Binaries" (PHOEBE) code, we analyzed some of the best eclipsing
binaries we discovered. Our results show that these studied systems turn out to
be ranging from detached to double-contact binaries, with low eccentricities
and high inclinations of approximately $80^{\circ}$. Their surface temperatures
range between $3500$K and $8000$K.
