Preliminary results for RR Lyrae stars and Classical Cepheids from the
  Vista Magellanic Cloud (VMC) Survey
  The Vista Magellanic Cloud (VMC, PI M.R. Cioni) survey is collecting
$K_S$-band time series photometry of the system formed by the two Magellanic
Clouds (MC) and the "bridge" that connects them. These data are used to build
$K_S$-band light curves of the MC RR Lyrae stars and Classical Cepheids and
determine absolute distances and the 3D geometry of the whole system using the
$K$-band period luminosity ($PLK_S$), the period - luminosity - color ($PLC$)
and the Wesenhiet relations applicable to these types of variables. As an
example of the survey potential we present results from the VMC observations of
two fields centered respectively on the South Ecliptic Pole and the 30 Doradus
star forming region of the Large Magellanic Cloud. The VMC $K_S$-band light
curves of the RR Lyrae stars in these two regions have very good photometric
quality with typical errors for the individual data points in the range of
$\sim$ 0.02 to 0.05 mag. The Cepheids have excellent light curves (typical
errors of $\sim$ 0.01 mag). The average $K_S$ magnitudes derived for both types
of variables were used to derive $PLK_S$ relations that are in general good
agreement within the errors with the literature data, and show a smaller
scatter than previous studies.
