EMU/GAMA: Understanding the link between dust geometry and star formation rate in galaxies
13 affiliations
- 1School of Mathematical and Physical Sciences, 12 Wally’s Walk, Macquarie University , NSW 2109 ,
- 2School of Chemistry, and Physics, Faculty of Science, Queensland University of Technology , Brisbane, QLD 4000 ,
- 3University of Southern Queensland, Centre for Astrophysics , West Street, Toowoomba, QLD 4350
- 4Astrophysics Group, School of Physics, University of Bristol , Tyndall Ave, Bristol BS8 1TL ,
- 5University of Wisconsin-Madison Department of Physics, , Madison, WI 53706-1390 ,
- 6University of Louisville Department of Physics and Astronomy, , Natural Science Building 102, Louisville, KY 40292 ,
- 7Ruhr-Universität Bochum, Astronomisches Institut , Universitätsstr 150 / GAFO03, 44801 Bochum ,
- 8Centre of Excellence for Data Science, AI, and Modelling (DAIM) , University of Hull, Cottingham Road, Kingston-upon-Hull, HU6 7RX ,
- 9Hamburger Sternwarte, Universität Hamburg , Gojenbergsweg 112, 21029 Hamburg ,
- 10International Centre for Radio Astronomy Research, University of Western Australia , 7 Fairway, Crawley, WA 6009 ,
- 11Research School of Astronomy & Astrophysics, The Australian National University , Mt Stromlo Observatory D.115, Cotter Rd, Weston Creek, ACT 2611 ,
- 12ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO-3D) ,
- 13University of Calgary Department of Physics and Astronomy, , Calgary, Alberta, T2N 1N4 ,
Abstract
We investigate the link between dust obscuration and star formation rate (SFR) estimators using Hα luminosities, LHα and radio luminosities, Lradio. While the Balmer Decrement (BD) is the standard tool for attenuating Hα, it can fail to account for optically thick dust regions from which Hα cannot escape. The ratio of SFRs estimated from radio luminosity and LHα corrected for dust attenuation using the BD can be used as a probe of the degree of optically thick dust affecting Hα. We explore this combining Evolutionary Map of the Universe (EMU) Early Science data at 887.5 MHz in the Galaxy and Mass Assembly (GAMA) G23 field with the GAMA data. We draw on dust estimates using both the BD and the dust mass, Md, demonstrating systematic underlying dependencies with Lradio/LHα. By combining the BD and Md, we quantify how they relate to Lradio/LHα and other galaxy properties. We use this approach to establish an Hα SFR (SFRHα) estimator that accounts for optically thick dust, demonstrating its consistency with conventional SFR indicators. Rather than proposing a replacement for standard correction methods, we aim to demonstrate the effectiveness of a dust geometry model that integrates both BD and Md parameters. This Hdust parameter provides a more physically complete representation of optically thick environments that traditional methods may overlook, and can produce SFR estimates consistent with traditional techniques.
Related
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BibTeX
@article{ahmed2026emugama,
title = {{EMU/GAMA: Understanding the link between dust geometry and star formation rate in galaxies}},
author = {U T Ahmed and A M Hopkins and B Farley and M Cowley and S Phillipps and Y A Gordon and B W Holwerda and D J Bomans and K A Pimbblet and S Casura and A Battisti and D A Leahy and J Prathap},
journal = {Monthly Notices of the Royal Astronomical Society},
year = {2026},
month = nov,
doi = {10.1093/mnras/stag2106},
url = {https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stag2106/9013655},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - EMU/GAMA: Understanding the link between dust geometry and star formation rate in galaxies
AU - U T Ahmed
AU - A M Hopkins
AU - B Farley
AU - M Cowley
AU - S Phillipps
AU - Y A Gordon
AU - B W Holwerda
AU - D J Bomans
AU - K A Pimbblet
AU - S Casura
AU - A Battisti
AU - D A Leahy
AU - J Prathap
PY - 2026
DA - 2026/11/05
JO - Monthly Notices of the Royal Astronomical Society
DO - 10.1093/mnras/stag2106
UR - https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stag2106/9013655
AB - We investigate the link between dust obscuration and star formation rate (SFR) estimators using Hα luminosities, LHα and radio luminosities, Lradio. While the Balmer Decrement (BD) is the standard tool for attenuating Hα, it can fail to account for optically thick dust regions from which Hα cannot escape. The ratio of SFRs estimated from radio luminosity and LHα corrected for dust attenuation using the BD can be used as a probe of the degree of optically thick dust affecting Hα. We explore this combining Evolutionary Map of the Universe (EMU) Early Science data at 887.5 MHz in the Galaxy and Mass Assembly (GAMA) G23 field with the GAMA data. We draw on dust estimates using both the BD and the dust mass, Md, demonstrating systematic underlying dependencies with Lradio/LHα. By combining the BD and Md, we quantify how they relate to Lradio/LHα and other galaxy properties. We use this approach to establish an Hα SFR (SFRHα) estimator that accounts for optically thick dust, demonstrating its consistency with conventional SFR indicators. Rather than proposing a replacement for standard correction methods, we aim to demonstrate the effectiveness of a dust geometry model that integrates both BD and Md parameters. This Hdust parameter provides a more physically complete representation of optically thick environments that traditional methods may overlook, and can produce SFR estimates consistent with traditional techniques.
SN - 0035-8711
SN - 1365-2966
ER -