2002AJ....124.2548J

We present the results of an extensive multiwavelength investigation of the source of far-infrared radiation in eight Sab-Sd galaxies using Brγ (λ=2.165 µm) as a tracer of star formation. In this analysis, we take into account extinction, using several recombination lines of hydrogen to assess extinction in each region analyzed. We compare these results with results of previous studies of this type. We find that using Brγ as a tracer of star formation, rather than the more commonly used Hα (λ=0.6563 µm) recombination line of hydrogen, yields more reliable results. We also compare the results found when using a global extinction of 1.1 mag with the results found using an assessment of extinction for each region and find that extinction must be assessed for each region. Finally, we use Starburst99 stellar models to perform an energy balance analysis that allows us to determine the most probable source of the far-infrared radiation. Our results indicate that the source of the far-infrared radiation is the youngest stellar population, indicating that far-infrared radiation can be used as a tracer of star formation. We also find that the dominant heating population is independent of far-infrared color temperature.