Dust Properties and Star-Formation Rates in Star-Forming Dwarf Galaxies

Abstract

We have used the Spitzer Space Telescope to study the dust properties of a sample of star-forming dwarf galaxies. The differences in the mid-infrared spectral energy distributions for these galaxies which, in general, are low metallicity systems, indicate differences in the physical properties, heating, and/or distribution of the dust. Specifically, these galaxies have more hot dust and/or very small grains and less PAH emission than either spiral or higher luminosity starburst galaxies. As has been shown in previous studies, there is a gradual decrease in PAH emission as a function of metallicity. Because much of the energy from star formation in galaxies is re-radiated in the mid-infrared, star-formation rate indicators based on both line and continuum measurements in this wavelength range are coming into more common usage. We show that the variations in the interstellar medium properties of galaxies in our sample, as measured in the mid-infrared, result in over an order of magnitude spread in the computed star-formation rates.

25 pages, 11 figures, 4 tables, ApJ accepted

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• Detection and characterization of detached tidal dwarf galaxies
• Exploring the evolution of star formation and dwarf galaxy properties with JWST/MIRI serendipitous spectroscopic surveys
• Infrared Properties of a Complete Sample of Star-Forming Dwarf Galaxies
• Dust and Gas as Seeds for Metal-Poor Star Formation
• Radio-to-Submillimetre Spectral Energy Distributions of NGC 1365