Integrated and resolved dust attenuation in clumpy star-forming galaxies at 0.07 < z < 0.14

Abstract

Dust attenuation in galaxies has been extensively studied nearby, however, there are still many unknowns regarding attenuation in distant galaxies. We contribute to this effort using observations of star-forming galaxies in the redshift range z = 0.05-0.15 from the DYnamics of Newly Assembled Massive Objects (DYNAMO) survey. Highly star-forming DYNAMO galaxies share many similar attributes to clumpy, star-forming galaxies at high redshift. Considering integrated Sloan Digital Sky Survey observations, trends between attenuation and other galaxy properties for DYNAMO galaxies are well matched to star-forming galaxies at high redshift. Integrated gas attenuations of DYNAMO galaxies are 0.2-2.0 mag in the V band and the ratio of E(B - V)(stars) and E(B - V)(gas) is 0.78-0.08 (compared to 0.44 at low redshift). Four highly star-forming DYNAMO galaxies were observed at Ha using the Hubble Space Telescope (HST) and at Pa alpha using integral field spectroscopy at Keck. The latter achieve similar resolution (similar to 0.8-1 kpc) to our HST imaging using adaptive optics, providing resolved observations of gas attenuations of these galaxies on sub-kiloparsec scales. We find <1.0 mag of variation in attenuation (at Ha) from clump to clump, with no evidence of highly attenuated star formation. Attenuations are in the range 0.3-2.2 mag in the V band, consistent with the attenuations of low-redshift star-forming galaxies. The small spatial variation on attenuation suggests that a majority of the star formation activity in these four galaxies occurs in relatively unobscured regions and thus star formation is well characterized by our Ha observations.