The local star formation rate density: assessing calibrations using [O ii], H and UV luminosities

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 [O II], H alpha 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 (GALEX) satellite. We examine the consistency of such methods using the star formation rate density 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 [O II]-derived SFR, commonly used at higher redshifts (z similar to 1), can be used to reliably estimate SFRs for ensembles of galaxies, but for high-mass galaxies (log(M-*/M-circle dot) greater than or similar to 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 [O II]-SFR.