UV-IR color profiles of the outer regions of 2K nearby S$^{4}$G galaxies
  We present our new, spatially-resolved, photometry in FUV and NUV from images
obtained by GALEX, and IRAC1 (3.6 $\mu$m) photometry obtained by the Spitzer
Space Telescope. We analyzed the surface brightness profiles $\mu_{\rm{FUV}}$,
$\mu_{\rm{NUV}}$, $\mu_{[3.6]}$, as well as the radial evolution of the
(FUV-NUV), (FUV - [3.6]), and (NUV - [3.6]) colors in the Spitzer Survey of
Stellar Structures in Galaxies (S$^{4}$G) galaxies (d$<$40 Mpc) sample. We
defined the GALEX Blue Sequence (GBS) and GALEX Red Sequence (GBR) from the
(FUV - NUV) versus (NUV - [3.6]) color-color diagram, populated by late-type
star forming galaxies and quiescent early-type galaxies respectively. While
most disk becomes radially bluer for GBS galaxies, and stay constant for GRS
galaxies, a large fraction ($>$50%) of intermediary GALEX Green Valley (GGV)
galaxies' outer disks are becoming redder. An outside-in quenching mechanism
such as environmentally-related mechanisms such as starvation or
ram-pressure-stripping could explain our results.
