NGDEEP: Anchoring the 0.5 < z < 3.5 Star-Forming Main Sequence at Low Stellar Masses with Ultradeep JWST/NIRISS WFSS
Abstract
Here we present deep JWST/NIRISS wide-field slitless spectroscopy (WFSS) that covers Hα and Hβ for galaxies at 0.5 < z < 3.5 in the NGDEEP survey. The NGDEEP NIRISS observations detect emission line fluxes from galaxies in the Hubble Ultra Deep Field to mF150W ≲ 28 mag, enabling studies of star-formation based on Hα (or Hβ, if necessary) in low-mass galaxies with log(M*/M⊙) ≳ 7 at z = 0.5 and log(M*/M⊙) ≳ 8 at z = 3.5. For 284 NGDEEP galaxies with >3σ detections of Hα or Hβ, we determine dust-corrected star-formation rates, SFRHα, via flux measurements of these Balmer lines and compare them to the galaxies' stellar masses to investigate the properties of the star-forming main sequence (SFMS) on short, ∼10~Myr timescales across three redshift bins. When we contrast the intrinsic scatter in the Hα--based SFMS to that of a SFMS comprised of UV--based SFRs, which trace star formation within the past ∼ 100~Myr, we find that the \Ha--based SFMS's intrinsic scatter (≈0.35−0.5~dex over 0.5 < z < 3.5) is ≈0.2−0.4~dex higher than the UV--based SFMS's intrinsic scatter at z < 2.5. We argue that brief (≲10~Myr) bursts of star formation likely account for this disparity in SFMS scatter. Theoretical predictions from the FIRE simulations underestimate the scatter we observe in the Hα--based SFMS at 1.5 < z < 2.5 and log(M*/M⊙) < 9 by up to ≈0.25~dex, which suggests that low-mass galaxies have burstier star-formation histories than expected on ≲10~Myr timescales.
Related
- The Stellar-Mass Dependence of Feedback-Driven Outflows in DESI DR1 Star-Forming Galaxies
- Investigating the young stellar populations and hierarchies in nearby galaxies with the UVIT. II. Presenting the properties of ~25,000 UV-detected star-forming clumps
- StAGE: Stellar Archaeology-driven Galaxy Evolution II. Binary Black Hole Mergers in Quiescent Galaxies and their Star-forming Progenitors
- Stellar discs and intermediate-mass black holes in galactic nuclei II. Fragmenting the disc and forming the S-stars in a live nuclear star cluster
- Balmer Break Measurements Trace Departures from the Star-Forming Main Sequence at 1<z<4 with JWST/NIRSpec
BibTeX
@misc{bolda2026ngdeep,
title = {{NGDEEP: Anchoring the $0.5 < z < 3.5$ Star-Forming Main Sequence at Low Stellar Masses with Ultradeep JWST/NIRISS WFSS}},
author = {Claire Bolda and Casey Papovich and Lu Shen and Nikko J. Cleri and L. Y. Aaron Yung and Vicente Estrada-Carpenter and Steven L. Finkelstein and Anton M. Koekemoer and Nor Pirzkal and Stephen M. Wilkins},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.40796},
eprint = {2610.40796},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.40796},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - NGDEEP: Anchoring the 0.5 < z < 3.5 Star-Forming Main Sequence at Low Stellar Masses with Ultradeep JWST/NIRISS WFSS
AU - Claire Bolda
AU - Casey Papovich
AU - Lu Shen
AU - Nikko J. Cleri
AU - L. Y. Aaron Yung
AU - Vicente Estrada-Carpenter
AU - Steven L. Finkelstein
AU - Anton M. Koekemoer
AU - Nor Pirzkal
AU - Stephen M. Wilkins
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.40796
UR - https://arxiv.org/abs/2610.40796
AB - Here we present deep JWST/NIRISS wide-field slitless spectroscopy (WFSS) that covers Hα and Hβ for galaxies at 0.5 < z < 3.5 in the NGDEEP survey. The NGDEEP NIRISS observations detect emission line fluxes from galaxies in the Hubble Ultra Deep Field to m_F150W ≲ 28 mag, enabling studies of star-formation based on Hα (or Hβ, if necessary) in low-mass galaxies with log(M_*/M_⊙) ≳ 7 at z = 0.5 and log(M_*/M_⊙) ≳ 8 at z = 3.5. For 284 NGDEEP galaxies with >3σ detections of Hα or Hβ, we determine dust-corrected star-formation rates, SFR_Hα, via flux measurements of these Balmer lines and compare them to the galaxies' stellar masses to investigate the properties of the star-forming main sequence (SFMS) on short, ∼10~Myr timescales across three redshift bins. When we contrast the intrinsic scatter in the Hα--based SFMS to that of a SFMS comprised of UV--based SFRs, which trace star formation within the past ∼ 100~Myr, we find that the \Ha--based SFMS's intrinsic scatter (≈0.35−0.5~dex over 0.5 < z < 3.5) is ≈0.2−0.4~dex higher than the UV--based SFMS's intrinsic scatter at z < 2.5. We argue that brief (≲10~Myr) bursts of star formation likely account for this disparity in SFMS scatter. Theoretical predictions from the FIRE simulations underestimate the scatter we observe in the Hα--based SFMS at 1.5 < z < 2.5 and log(M_*/M_⊙) < 9 by up to ≈0.25~dex, which suggests that low-mass galaxies have burstier star-formation histories than expected on ≲10~Myr timescales.
ER -