The Spitzer Survey of Stellar Structure in Galaxies (S4G): Stellar
  Masses, Sizes and Radial Profiles for 2352 Nearby Galaxies
  The Spitzer Survey of Stellar Structure in Galaxies (S4G) is a volume,
magnitude, and size-limited survey of 2352 nearby galaxies with deep imaging at
3.6 and 4.5um. In this paper we describe our surface photometry pipeline and
showcase the associated data products that we have released to the community.
We also identify the physical mechanisms leading to different levels of central
stellar mass concentration for galaxies with the same total stellar mass.
Finally, we derive the local stellar mass-size relation at 3.6um for galaxies
of different morphologies. Our radial profiles reach stellar mass surface
densities below 1 Msun pc-2. Given the negligible impact of dust and the almost
constant mass-to-light ratio at these wavelengths, these profiles constitute an
accurate inventory of the radial distribution of stellar mass in nearby
galaxies. From these profiles we have also derived global properties such as
asymptotic magnitudes (and the corresponding stellar masses), isophotal sizes
and shapes, and concentration indices. These and other data products from our
various pipelines (science-ready mosaics, object masks, 2D image
decompositions, and stellar mass maps), can be publicly accessed at IRSA
(http://irsa.ipac.caltech.edu/data/SPITZER/S4G/).
