Star Formation and Nebular Attenuation from Paα, Brα, and Brβ in Massive Dust-obscured Galaxies at Cosmic Noon using JWST

@misc{vanicek2026star,
  title = {{Star Formation and Nebular Attenuation from Pa$α$, Br$α$, and Br$β$ in Massive Dust-obscured Galaxies at Cosmic Noon using JWST}},
  author = {Virginia Vanicek and Jed McKinney and Alexandra Pope and Anna Sajina and Stacey Alberts and Meredith Stone and Lee Armus and Sinclaire M. Manning and Olivia Cooper and Tanio DÍaz-Santos and Miriam Eleazer and Caitlin Casey and Thomas S. -Y. Lai and Steven Finkelstein and Leonid Sajkov and Allison Kirkpatrick and Anthony Taylor},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.22428},
  eprint = {2609.22428},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.22428},
}

TY  - UNPB
TI  - Star Formation and Nebular Attenuation from Paα, Brα, and Brβ in Massive Dust-obscured Galaxies at Cosmic Noon using JWST
AU  - Virginia Vanicek
AU  - Jed McKinney
AU  - Alexandra Pope
AU  - Anna Sajina
AU  - Stacey Alberts
AU  - Meredith Stone
AU  - Lee Armus
AU  - Sinclaire M. Manning
AU  - Olivia Cooper
AU  - Tanio DÍaz-Santos
AU  - Miriam Eleazer
AU  - Caitlin Casey
AU  - Thomas S. -Y. Lai
AU  - Steven Finkelstein
AU  - Leonid Sajkov
AU  - Allison Kirkpatrick
AU  - Anthony Taylor
PY  - 2026
DA  - 2026/09/18
PB  - arXiv
DO  - 10.48550/arxiv.2609.22428
UR  - https://arxiv.org/abs/2609.22428
AB  - Near-infrared hydrogen recombination lines can provide robust star-formation rates if the effects of dust attenuation continue to diminish towards longer wavelengths. To quantify near-infrared attenuation and ultimately measure accurate star-formation rates (SFRs) at the height of cosmic star-formation, we present Paα, Brα, and Brβ detections in $27$ luminous infrared galaxies at z∼ 1−2, including pure star-forming galaxies as well as dust-obscure Active Galactic Nuclei (AGN). Using combined spectra from the JWST MIRI (Mid-Infrared Instrument) LRS (Low Resolution Spectrometer) and the Spitzer Space Telescope IRS we quantify the star formation rates of our sample using a sub-sample of 13 galaxies detected in Paα emission (1.87 μm), 14 galaxies detected in Brα (4.05 μm), and 12 galaxies detected in Brβ (2.63 μm). By combining multiple near-infrared recombination lines in individual galaxies we calculate nebular attenuation, finding A_λ∼3 mag at ∼2 μm and A_λ∼1 mag at ∼4 μm. Nebular lines trace the SFR on ∼ 10 Myr timescales, which we compare to the total infrared luminosity (L_IR) which probes the star formation over the last ∼ 100 Myr. SFRs measured from L_IR using common conversions are systematically higher than the SFRs derived from attenuation-corrected nebular line measurements by a factor of ∼2.5. This could be indicative of a declining or static star formation history with a past burst or systematic effects on SFR_IR such as dust heating from evolved stellar populations, and/or an active galactic nucleus.
ER  -