We explore the use of simple star-formation rate (SFR) indicators (such as
may be used in high-redshift galaxy surveys) in the local Universe using [OII],
Ha, and u-band luminosities from the deeper 275 deg^2 Stripe 82 subsample of
the Sloan Digital Sky Survey (SDSS) coupled with UV data from the Galaxy
Evolution EXplorer satellite (GALEX). We examine the consistency of such
methods using the star-formation rate density (SFRD) as a function of stellar
mass in this local volume, and quantify the accuracy of corrections for dust
and metallicity on the various indicators. Rest-frame u-band promises to be a
particularly good SFR estimator for high redshift studies since it does not
require a particularly large or sensitive extinction correction, yet yields
results broadly consistent with more observationally expensive methods. We
suggest that the [OII]-derived SFR, commonly used at higher redshifts (z~1),
can be used to reliably estimate SFRs for ensembles of galaxies, but for high
mass galaxies (log(M*/Msun)>10), a larger correction than is typically used is
required to compensate for the effects of metallicity dependence and dust
extinction. We provide a new empirical mass-dependent correction for the
[OII]-SFR.Comment: 22 pages, 16 figures. This version corrects typos in equations 2, 7,
and 9 of the published version, as described in the MNRAS Erratum. Published
results are unaffected. A simple piece of IDL Code for applying the
mass-dependent correction to [OII] SFR available from
http://astro.uwaterloo.ca/~dgilbank/data/corroii.pr
