A panchromatic spatially-resolved analysis of nearby galaxies -- I.
  Sub-kpc scale Main Sequence in grand-design spirals
  We analyse the spatially resolved relation between stellar mass (M$_{\star}$)
and star formation rate (SFR) in disk galaxies (i.e. the Main Sequence, MS).
The studied sample includes eight nearby face-on grand-design spirals, e.g. the
descendant of high-redshift, rotationally-supported star-forming galaxies. We
exploit photometric information over 23 bands, from the UV to the far-IR, from
the publicly available DustPedia database to build spatially resolved maps of
stellar mass and star formation rates on sub-galactic scales of 0.5-1.5 kpc, by
performing a spectral energy distribution fitting procedure that accounts for
both the observed and the obscured star formation processes, over a wide range
of internal galaxy environments (bulges, spiral arms, outskirts). With more
than 30 thousands physical cells, we have derived a definition of the local
spatially resolved MS per unit area for disks,
$\log(\Sigma_{SFR})$=0.82log$(\Sigma_{*})$-8.69. This is consistent with the
bulk of recent results based on optical IFU, using the H$\alpha$ line emission
as a SFR tracer. Our work extends the analysis at lower sensitivities in both
M$_{\star}$ and SFR surface densities, up to a factor $\sim$ 10. The self
consistency of the MS relation over different spatial scales, from sub-galactic
to galactic, as well as with a rescaled correlation obtained for high redshift
galaxies, clearly proves its universality.
