Program: GN-2006A-Q-26

The conversion of measured luminosities from star-forming activity to star-formation rates depends upon metallicity, as gauged by gas-phase metallicities in star-forming galaxies. Recent work (e.g., Hirashita et al. 2003) has calibrated the conversion factors at high-metallicities. We propose to obtain with GMOS North multi-object spectroscopy of HII regions in 13 dwarf irregular galaxies in the M81 group to augment ongoing efforts with the Spitzer SINGS Legacy Survey, an HST Cycle14-GO ACS proposal to derive the history of star-formation from resolved stars, and a deep library of additional multiwavelength data from radio-continuum to X-rays. The high-quality GMOS spectra and subsequent derived nebular oxygen abundances will be combined with infrared data to help pin down the conversion factors between measured luminosity and star-formation rates at low- (sub-solar) metallicities. The present data will directly bear upon the interpretation of star-formation in low-mass objects at high redshifts.