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Paper: Obscured Star Formation in SINGS Galaxies
Volume: 381, The Second Annual Spitzer Science Center Conference: Infrared Diagnostics of Galaxy Evolution
Page: 181
Authors: Prescott, M.K.M.; Kennicutt, R.C.; the SINGS Team
Abstract: Using multi-wavelength data from the Spitzer Infrared Nearby Galaxies Survey (SINGS) and a new empirical method for deriving attenuation of infrared-selected star-forming regions, we investigate the statistics of obscured star formation in a sample of 18 nearby galaxies. We find that the galaxies in this sample are in general very well-behaved in terms of their attenuation properties on 500 pc scales. There is no evidence in this work for a large subpopulation of highly-obscured star-forming regions on these scales; the regions in the highly-obscured tail of the attenuation distribution (A > 3.3) make up only ∼5% of the sample of more than 1100 regions. These highly-obscured cases are generally the central regions of luminous galaxies with high overall attenuation, are themselves somewhat more luminous, but are not otherwise remarkable. We also find that a majority of the galaxies show decreasing radial trends in Hα attenuation. The small fraction of highly-obscured regions seen in this sample of normal, star-forming galaxies suggests that on these large spatial scales the timescale for significant dispersal or break up of optically thick dust clouds is short relative to the lifetime of a typical star-forming region.
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