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The AURORA Survey: Ionizing Photon Production Efficiency with Minimal Nebular Dust Attenuation Systematics

Astrophysics of Galaxies 2025-10-15 v1

Abstract

We present ionizing photon production efficiencies (ξion{\xi}_{\rm ion}) for 63 z=1.5-6.9 star-forming galaxies using precise nebular dust attenuation corrections from the JWST/AURORA survey. A subset of objects within AURORA have individually-determined nebular dust attenuation curves, which vary significantly in shape and normalization, resulting in reduced systematic uncertainty when constraining the total attenuation of Hα{\alpha} luminosity, and thus the intrinsic ionizing output within our sample. We find evidence for positive correlations between ξion{\xi}_{\rm ion} and redshift, equivalent width of [OIII]λ{\lambda}5007, and O32=[OIII]λ{\lambda}5007/[OII]λ{\lambda}3726,3729, and negative correlations between ξion{\xi}_{\rm ion} and stellar attenuation, UV luminosity (LUV_{\rm UV}), stellar mass, and direct-method metallicity. We test alternate dust prescriptions within this sample, and find that the total attenuation is lower when using the commonly-assumed Galactic extinction curve or when assuming that stellar attenuation is equal to nebular attenuation. We also find that assuming either of these alternate dust prescriptions can change the slope of relationships between ξion{\xi}_{\rm ion} and galaxy property, notably inducing a flat trend between ξion{\xi}_{\rm ion} and LUV_{\rm UV} within AURORA. While the novel nebular dust curves derived from AURORA spectroscopy reveal obscured ionizing photon production within star-forming galaxies at these redshifts, a more complete understanding of stellar attenuation is required to fully reduce dust systematics on ξion{\xi}_{\rm ion} for inclusion in reionization models.

Keywords

Cite

@article{arxiv.2510.12177,
  title  = {The AURORA Survey: Ionizing Photon Production Efficiency with Minimal Nebular Dust Attenuation Systematics},
  author = {Anthony J. Pahl and Alice Shapley and Naveen A. Reddy and Ryan Sanders and Michael W. Topping and Danielle A. Berg and Callum T. Donnan and James S. Dunlop and Richard S. Ellis and N. M. Förster Schreiber and K. Glazebrook and Derek J. McLeod and Max Pettini and Daniel Schaerer},
  journal= {arXiv preprint arXiv:2510.12177},
  year   = {2025}
}

Comments

20 pages, 7 figures, submitted to ApJ