A unified picture of breaks and truncations in spiral galaxies from SDSS
  and S^{4}G imaging
  The mechanism causing breaks in the radial surface brightness distribution of
spiral galaxies is not yet well known. Despite theoretical efforts, there is
not a unique explanation for these features and the observational results are
not conclusive. In an attempt to address this problem, we have selected a
sample of 34 highly inclined spiral galaxies present both in the Sloan Digital
Sky Survey and in the Spitzer Survey of Stellar Structure in Galaxies. We have
measured the surface brightness profiles in the five Sloan optical bands and in
the 3.6$\mu m$ Spitzer band. We have also calculated the color and stellar
surface mass density profiles using the available photometric information,
finding two differentiated features: an innermost break radius at distances of
$\sim 8 \pm 1$ kpc [$0.77 \pm 0.06$ $R_{25}$] and a second characteristic
radius, or truncation radius, close to the outermost optical extent ($\sim 14
\pm 2$ kpc [$1.09 \pm 0.05$ $R_{25}$]) of the galaxy. We propose in this work
that the breaks might be a phenomena related to a threshold in the star
formation, while truncations are more likely a real drop in the stellar mass
density of the disk associated with the maximum angular momentum of the stars.
