The Stellar Populations and Rest-frame Colors of Star-forming Galaxies at z ≈ 8: Exploring the Impact of Filter Choice and Star Formation History Assumption with JADES

@article{helton2026stellar,
  title = {{The Stellar Populations and Rest-frame Colors of Star-forming Galaxies at z ≈ 8: Exploring the Impact of Filter Choice and Star Formation History Assumption with JADES}},
  author = {Jakob Helton and Stacey Alberts and George Rieke and Kevin Hainline and Zhiyuan Ji and Marcia Rieke and Benjamin Johnson and Brant Robertson and Sandro Tacchella and Lily Whitler and William Baker and Rachana Bhatawdekar and Kristan Boyett and Andrew Bunker and Phillip Cargile and Stefano Carniani and Stephane Charlot and Jacopo Chevallard and Emma Curtis-Lake and Eiichi Egami and Daniel Eisenstein and Ryan Hausen and Jianwei Lyu and Roberto Maiolino and Erica Nelson and Pablo Pérez-González and Pierluigi Rinaldi and Meredith Stone and Fengwu Sun and Christina Williams and Christopher Willmer and Chris Willott and Joris Witstok},
  journal = {The Astrophysical Journal},
  year = {2026},
  month = jul,
  doi = {10.3847/1538-4357/ae5dcd},
  eprint = {2506.02099},
  archivePrefix = {arXiv},
  url = {https://hal.science/hal-05760806v1},
  note = {CC BY 4.0},
}

TY  - JOUR
TI  - The Stellar Populations and Rest-frame Colors of Star-forming Galaxies at z ≈ 8: Exploring the Impact of Filter Choice and Star Formation History Assumption with JADES
AU  - Jakob Helton
AU  - Stacey Alberts
AU  - George Rieke
AU  - Kevin Hainline
AU  - Zhiyuan Ji
AU  - Marcia Rieke
AU  - Benjamin Johnson
AU  - Brant Robertson
AU  - Sandro Tacchella
AU  - Lily Whitler
AU  - William Baker
AU  - Rachana Bhatawdekar
AU  - Kristan Boyett
AU  - Andrew Bunker
AU  - Phillip Cargile
AU  - Stefano Carniani
AU  - Stephane Charlot
AU  - Jacopo Chevallard
AU  - Emma Curtis-Lake
AU  - Eiichi Egami
AU  - Daniel Eisenstein
AU  - Ryan Hausen
AU  - Jianwei Lyu
AU  - Roberto Maiolino
AU  - Erica Nelson
AU  - Pablo Pérez-González
AU  - Pierluigi Rinaldi
AU  - Meredith Stone
AU  - Fengwu Sun
AU  - Christina Williams
AU  - Christopher Willmer
AU  - Chris Willott
AU  - Joris Witstok
PY  - 2026
DA  - 2026/07/13
JO  - The Astrophysical Journal
DO  - 10.3847/1538-4357/ae5dcd
UR  - https://hal.science/hal-05760806v1
AB  - Our understanding of the physical properties of star-forming galaxies during the Epoch of Reionization (EoR; at z > 6) suffers from degeneracies among the apparent properties of the stars, nebular gas, and dust. These degeneracies are most prominent with photometry, which has insufficient (1) spectral resolution and (2) rest-frame spectral coverage. We explore ways to break these degeneracies with a sample of N = 22 high-redshift star-forming galaxies at 7 < z phot ≤ 9, using some of the deepest existing imaging from JWST/NIRCam and JWST/MIRI with JADES. Key to this study is the imaging from JWST/MIRI at 7.7 μ m, which provides coverage of the rest-frame I band at the observed redshifts. We infer stellar population properties and rest-frame colors using a variety of filter sets and star formation history (SFH) assumptions to explore the impact of these choices. Evaluating these quantities both with and without the 7.7 μ m data point shows that dense spectral coverage with JWST/NIRCam (eight or more filters, including at least one medium-band at λ obs ≈ 4–5 μ m) can compensate for lacking the rest-frame I -band coverage for the vast majority (≈80%) of our sample. Furthermore, these galaxy properties are most consistently determined by assuming the delayed-tau SFH, which provides the smallest offsets and scatters around these offsets when including JWST/MIRI. Within extragalactic surveys like JADES and CEERS, our findings suggest that robust characterization of the stellar population properties and rest-frame colors for typical high-redshift star-forming galaxies (i.e., galaxies with M UV ≈ −20 and β UV ≈ −2) is possible with JWST/NIRCam alone at z ≈ 8.
SN  - 0004-637X
SN  - 1538-4357
ER  -