We combine data from the Sloan Digital Sky Survey (SDSS), the Galaxy Evolution Explorer (GALEX), and the Spitzer Space Telescope to create a sample of galaxies observed homogeneously from the UV to the far-IR. This sample, consisting of ∼460 galaxies observed spectroscopically by the SDSS, provides us with a multiwavelength (0.15-24 mm) view of obscured and unobscured star formation in nearby (z ≤ 0.3) galaxies with star formation rates (SFRs) ranging from 0.01 to 100 M·yr-1. We calculate a robust dust measure from the infraredto-UV ratio (or infrared excess [IRX]) and explore the influence of star formation history (SFH) on the dust-UV color relation (i.e., the IRX-β relation). We find that the UV colors of galaxies are only weakly dependent on their SFH as measured by the 4000 break. However, we find that the contributions of dust and SFH are distinguishable when colors at widely separated wavelengths (e.g., 0.23-3.6 mm) are introduced. We show this explicitly by recasting the IRX-b relation as a more general IRX-SFH-color relation, which we examine in different projections. We also determine simple fits to this relation.
Bibliographical noteFunding Information:
The MPA/JHU collaboration for SDSS studies has very generously made their catalogs publicly available. The publicly available Spitzer data obtained and reduced by the SWIRE team have been essential to this work. B. D. J. would like to thank Eric Bell for illuminating comments. We gratefully acknowledge NASA’s support for construction, operation, and science analysis for the GALEX mission, developed in cooperation with the Centre National d’Etudes Spatiale of France and the Korean Ministry of Science and Technology. B. D. J. was supported by NASA GSRP grant NNG05GO43H.
© 2006. The American Astronomical Society. All rights reserved.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science