The Star Formation Reference Survey. IV. Stellar mass distribution of
  local star-forming galaxies
  We constrain the mass distribution in nearby, star-forming galaxies with the
Star Formation Reference Survey (SFRS), a galaxy sample constructed to be
representative of all known combinations of star formation rate (SFR), dust
temperature, and specific star formation rate (sSFR) that exist in the Local
Universe. An innovative two-dimensional bulge/disk decomposition of the
2MASS/$K_{s}$-band images of the SFRS galaxies yields global luminosity and
stellar mass functions, along with separate mass functions for their bulges and
disks. These accurate mass functions cover the full range from dwarf galaxies
to large spirals, and are representative of star-forming galaxies selected
based on their infra-red luminosity, unbiased by AGN content and environment.
We measure an integrated luminosity density $j$ = 1.72 $\pm$ 0.93 $\times$
10$^{9}$ L$_{\odot}$ $h^{-1}$ Mpc$^{-3}$ and a total stellar mass density
$\rho_{M}$ = 4.61 $\pm$ 2.40 $\times$ 10$^{8}$ M$_{\odot}$ $h^{-1}$ Mpc$^{-3}$.
While the stellar mass of the \emph{average} star-forming galaxy is equally
distributed between its sub-components, disks globally dominate the mass
density budget by a ratio 4:1 with respect to bulges. In particular, our
functions suggest that recent star formation happened primarily in massive
systems, where they have yielded a disk stellar mass density larger than that
of bulges by more than 1 dex. Our results constitute a reference benchmark for
models addressing the assembly of stellar mass on the bulges and disks of local
($z = 0$) star-forming galaxies.
