We investigate star formation rate (SFR) calibrations in light of recentdevelopments in the modeling of stellar rotation. Using new publishednon-rotating and rotating stellar tracks, we study the integrated properties ofsynthetic stellar populations and find that the UV to SFR calibration for therotating stellar population is 30% smaller than for the non-rotating stellarpopulation, and 40% smaller for the Halpha to SFR calibration. These reductionstranslate to smaller SFR estimates made from observed UV and Halphaluminosities. Using the UV and Halpha fluxes of a sample of ~300 localgalaxies, we derive a total (i.e., sky-coverage corrected) SFR within 11 Mpc of120-170 Msun/yr and 80-130 Msun/yr for the non-rotating and rotatingestimators, respectively. Independently, the number of core-collapse supernovaediscovered in the same volume requires a total SFR of 270^{+110}_{-80} Msun/yr,suggesting a mild tension with the SFR estimates made with rotatingcalibrations. More generally, when compared with the estimated SFR, the localsupernova discoveries strongly constrain any physical effects that mightincrease the energy output of massive stars, including, but not limited to,stellar rotation. The cosmic SFR and cosmic supernova rate data on the otherhand show the opposite trend, with the cosmic SFR almost double that inferredfrom cosmic supernovae, constraining a significant decrease in the energyoutput of massive stars. Together, these lines of evidence suggest that thetrue SFR calibration factors cannot be too far from their canonical values.
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