Dust Attenuation in Clumpy, Star-Forming Galaxies at 0.07 < z < 0.14

TL;DR

This study investigates dust attenuation in star-forming galaxies at intermediate redshifts, revealing that attenuation varies little across regions and is comparable to local galaxies, enhancing understanding of dust effects in galaxy evolution.

Contribution

The paper provides new resolved measurements of dust attenuation in distant, clumpy star-forming galaxies, bridging the gap between local and high-redshift galaxy observations.

Findings

Gas attenuation ranges from 0.2 to 2.0 mags in V-band.

Attenuation variation across regions is less than 1 mag.

Star formation occurs mainly in unobscured regions.

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 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 mags in the V-band, and the ratio of stellar E(B-V) and gas E(B-V) is 0.78-0.08 (compared to 0.44 at low redshift). Four highly star-forming DYNAMO galaxies were observed at H-alpha using the Hubble Space Telescope and at Pa-alpha using integral field spectroscopy at Keck. The latter achieve similar resolution (~0.8-1 kpc) to our HST imaging using adaptive optics, providing resolved observations of gas attenuations of these galaxies on sub-kpc scales. We find < 1.0 mag of variation in attenuation (at H-alpha) from clump to clump, with no evidence of highly attenuated star formation. Attenuations are in the range 0.3-2.2 mags in the V band, consistent with 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 characterised by our H-alpha observations.