The VMC survey - XXXI. The spatially resolved star formation history of
  the main body of the Small Magellanic Cloud
  We recover the spatially resolved star formation history across the entire
main body and Wing of the Small Magellanic Cloud (SMC), using fourteen deep
tile images from the VISTA survey of the Magellanic Clouds (VMC), in the YJKs
filters. The analysis is performed on 168 subregions of size 0.143 deg2,
covering a total contiguous area of 23.57 deg2. We apply a colour-magnitude
diagram (CMD) reconstruction method that returns the best-fitting star
formation rate SFR(t), age--metallicity relation, distance and mean reddening,
together with their confidence intervals, for each subregion. With respect to
previous analyses, we use a far larger set of VMC data, updated stellar models,
and fit the two available CMDs (Y-Ks versus Ks and J-Ks versus Ks)
independently. The results allow us to derive a more complete and more reliable
picture of how the mean distances, extinction values, star formation rate, and
metallicities vary across the SMC, and provide a better description of the
populations that form its Bar and Wing. We conclude that the SMC has formed a
total mass of (5.31+-0.05)x10^8 Msun in stars over its lifetime. About two
thirds of this mass is expected to be still locked in stars and stellar
remnants. 50 per cent of the mass was formed prior to an age of 6.3 Gyr, and 80
per cent was formed between 8 and 3.5 Gyr ago. We also illustrate the likely
distribution of stellar ages and metallicities in different parts of the CMD,
to aid the interpretation of data from future astrometric and spectroscopic
surveys of the SMC.
