The Dragonfly Wide Field Survey. II. Accurate Total Luminosities and
  Colors of Nearby Massive Galaxies and Implications for the Galaxy Stellar
  Mass Function
  Stellar mass estimates of massive galaxies are susceptible to systematic
errors in their photometry, due to their extended light profiles. In this study
we use data from the Dragonfly Wide Field Survey (DWFS) to accurately measure
the total luminosities and colors of nearby massive galaxies. The low surface
brightness limits of the survey ($\mu_g \approx $ 31 mag arcsec $^{-2}$ on a
one arcmin scale) allows us to implement a method, based on integrating the 1-D
surface brightness profile, that is minimally dependent on any
parameterization. We construct a sample of 1188 massive galaxies with $\log
M_*/M_\odot > 10.75$ based on the Galaxy Mass and Assembly (GAMA) survey and
measure their total luminosities and $g-r$ colors. We then compare our
measurements to various established methods applied to imaging from the Sloan
Digital Sky Survey (SDSS), focusing on those favored by the GAMA survey. In
general, we find that galaxies are brighter in the $r$ band by an average of
${\sim}0.05$ mag and bluer in $g-r$ colors by $\sim 0.06$ mag compared to the
GAMA measurements. These two differences have opposite effects on the stellar
mass estimates. The total luminosities are larger by $5\%$ but the
mass-to-light ratios are lower by $\sim 10\%$. The combined effect is that the
stellar mass estimate of massive galaxies decreases by $7\%$. This, in turn,
implies a small change in number density of massive galaxies: $\leq 30\%$ at
$\log M_*/M_\odot \geq 11$.
