The panchromatic view of the Magellanic Clouds from Classical Cepheids.
  I. Distance, Reddening and Geometry of the Large Magellanic Cloud disk
  We present a detailed investigation of the Large Magellanic Cloud (LMC) disk
using classical Cepheids. Our analysis is based on optical (I,V; OGLE-IV),
near-infrared (NIR: J,H,Ks) and mid-infrared (MIR: w1; WISE) mean magnitudes.
By adopting new templates to estimate the NIR mean magnitudes from single-epoch
measurements, we build the currently most accurate, largest and homogeneous
multi-band dataset of LMC Cepheids. We determine Cepheid individual distances
using optical and NIR Period-Wesenheit relations (PWRs), to measure the
geometry of the LMC disk and its viewing angles. Cepheid distances based on
optical PWRs are precise at 3%, but accurate to 7, while the ones based on NIR
PWRs are more accurate (to 3%), but less precise (2%-15%), given the higher
photometric error on the observed magnitudes. We found an inclination i=25.05
$\pm$ 0.02 (stat.) $\pm$ 0.55 (syst.) deg, and a position angle of the lines of
nodes P.A.=150.76 $\pm$ 0.02(stat.) $\pm$ 0.07(syst.) deg. These values agree
well with estimates based either on young (Red Supergiants) or on
intermediate-age (Asymptotic Giant Branch, Red Clump) stellar tracers, but they
significantly differ from evaluations based on old (RR Lyrae) stellar tracers.
This indicates that young/intermediate and old stellar populations have
different spatial distributions. Finally, by using the reddening-law fitting
approach, we provide a reddening map of the LMC disk which is ten times more
accurate and two times larger than similar maps in the literature. We also
found an LMC true distance modulus of $\mu_{0,LMC}=18.48 \pm 0.10$ (stat. and
syst.) mag, in excellent agreement with the currently most accurate measurement
(Pietrzynski et al. 2013).
