THE CALIBRATION OF STAR FORMATION RATE INDICATORS FOR WISE 22 μm-SELECTED GALAXIES IN THE SLOAN DIGITAL SKY SURVEY

We study star formation rate (SFR) indicators for Wide-field Infrared Survey Explorer (WISE) 22 mu m-selected, star-forming galaxies at 0.01 < z < 0.3 in the Sloan Digital Sky Survey. Using extinction-corrected H alpha luminosities and total infrared luminosities as reference SFR estimates, we calibrate WISE mid-infrared- (MIR-) related SFR indicators. Both the 12 and 22 mu m monochromatic luminosities correlate well with the reference the SFR estimates, but tend to underestimate the SFRs of metal-poor galaxies (at lower than solar metallicity), consistent with previous studies. We mitigate this metallicity dependence by using a linear combination of observed H alpha and WISE MIR luminosities for our SFR estimates. This combination provides SFR measurements as robust as those applied to Spitzer data by Kennicutt et al. However, we find that the coefficient a in L-H alpha(obs) + aL(MIR) increases with the SFR, and show that a nonlinear combination of observed Ha and MIR luminosities gives the best SFR estimates with small scatters and with little dependence on physical parameters. Such a combination of H alpha and MIR luminosities for SFR estimates is first applied to the WISE data. Using WISE data, we provide several SFR recipes that are applicable to galaxies with 0.1 less than or similar to SFR (M-circle dot yr(-1)) less than or similar to 100.