Abstract
We investigate dust attenuation and its dependence on viewing angle for 308 star-forming galaxies at 1.3 < = z < = 2.6 from the MOSFIRE Deep Evolution Field survey. We divide galaxies with a detected Hα emission line and coverage of Hβ into eight groups by stellar mass, star formation rate (SFR), and inclination (i.e., axis ratio), and we then stack their spectra. From each stack, we measure the Balmer decrement and gas-phase metallicity, and then we compute the median AV and UV continuum spectral slope (β). First, we find that none of the dust properties (Balmer decrement, AV , or β) varies with the axis ratio. Second, both stellar and nebular attenuation increase with increasing galaxy mass, showing little residual dependence on SFR or metallicity. Third, nebular emission is more attenuated than stellar emission, and this difference grows even larger at higher galaxy masses and SFRs. Based on these results, we propose a three-component dust model in which attenuation predominantly occurs in star-forming regions and large, dusty star-forming clumps, with minimal attenuation in the diffuse ISM. In this model, nebular attenuation primarily originates in clumps, while stellar attenuation is dominated by star-forming regions. Clumps become larger and more common with increasing galaxy mass, creating the above mass trends. Finally, we argue that a fixed metal yield naturally leads to mass regulating dust attenuation. Infall of low-metallicity gas increases the SFR and lowers the metallicity, but leaves the dust column density mostly unchanged. We quantify this idea using the Kennicutt–Schmidt and fundamental metallicity relations, showing that galaxy mass is indeed the primary driver of dust attenuation.
Document Type
Article
Publication Date
2023
Digital Object Identifier (DOI)
https://doi.org/10.3847/1538-4357/accdd1
Funding Information
We thank the referee for a thorough and thoughtful report. B.L. thanks Daniel D. Kelson for the inspiration for this project. We would like to thank Robert Feldmann for useful discussions regarding the interpretation of results. This research is based on observations made with the NASA/ESA Hubble Space Telescope obtained from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program HST-AR-16141.001-A. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under grant No. DGE 2146752. We also acknowledge support from NSF AAG grant Nos. AST-1312780, 1312547, 1312764, 1313171, 2009313, and 2009085, grant No. AR-13907 from the Space Telescope Science Institute, and grant No. NNX16AF54G from the NASA ADAP program. We wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Repository Citation
Lorenz, Brian; Kriek, Mariska; Shapley, Alice E.; Reddy, Naveen; Sanders, Ryan L.; Barro, Guillermo; Coil, Alison L.; Mobasher, Bahram; Price, Sedona H.; Runco, Jordan N.; Shivaei, Irene; Siana, Brian; and Weisz, Daniel R., "An Updated Dust-to-Star Geometry: Dust Attenuation Does Not Depend on Inclination in 1.3 <= z <= 2.6 Star-forming Galaxies from MOSDEF" (2023). Physics and Astronomy Faculty Publications. 692.
https://uknowledge.uky.edu/physastron_facpub/692
Notes/Citation Information
© 2023. The Author(s). Published by the American Astronomical Society.
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