Comparing Infrared Star-Formation Rate Indicators with Optically-Derived Quantities

Abstract

We examine the UV reprocessing efficiencies of warm dust and polycyclic aromatic hydrocarbons (PAHs) through an analysis of the mid- and far-infrared surface luminosity densities of 85 nearby H$\alpha$-selected star-forming galaxies detected by the volume-limited KPNO International Spectroscopic Survey (KISS). Because H$\alpha$ selection is not biased toward continuum-bright objects, the KISS sample spans a wide range in stellar masses ($10^8$-$10^{12}{\mathrm{M}}_{\odot }$), as well as H$\alpha$ luminosity ($10^{39}$-$10^{43}ergs/s$), mid-infrared 8.0$\mu$m luminosity ($10^{41}$-$10^{44}ergs/s$), and [Bw-R] color (-.1-2.2). We find that mid-infrared polycyclic aromatic hydrocarbon (PAH) emission in the Spitzer IRAC 8.0$\mu$m band correlates with star formation, and that the efficiency with which galaxies reprocess UV energy into PAH emission depends on metallicity. We also find that the relationship between far-infrared luminosity in the Spitzer MIPS 24$\mu$m band pass and H$\alpha$-measured star-formation rate varies from galaxy to galaxy within our sample; we do not observe a metallicity dependence in this relationship. We use optical colors and established mass-to-light relationships to determine stellar masses for the KISS galaxies; we compare these masses to those of nearby galaxies as a confirmation that the volume-limited nature of KISS avoids strong biases. We also examine the relationship between IRAC 3.6$\mu$m luminosity and galaxy stellar mass, and find a color-dependent correlation between the two.

15 pages, 10 figures

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• The Spitzer Deep, Wide-Field Survey
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Cited by in corpus (1)

• SFR estimations from z=0 to z=0.9 -- A comparison of SFR calibrators for star-forming galaxies