TY - JOUR
T1 - A Spectroscopic Analysis of the Ionizing Photon Production Efficiency in JADES and CEERS
T2 - Implications for the Ionizing Photon Budget
AU - Pahl, Anthony
AU - Topping, Michael W.
AU - Shapley, Alice
AU - Sanders, Ryan
AU - Reddy, Naveen A.
AU - Clarke, Leonardo
AU - Kehoe, Emily
AU - Bento, Trinity
AU - Brammer, Gabe
N1 - Publisher Copyright:
© 2025. The Author(s). Published by the American Astronomical Society.
PY - 2025/3/10
Y1 - 2025/3/10
N2 - We have used a combined sample of JADES and CEERS objects in order to constrain ionizing photon production efficiency (ξion) from JWST/NIRSpec and JWST/NIRCam data. We examine 163 objects at 1.06 < z < 6.71 with significant (3σ) spectroscopic detections of Hα and Hβ in order to constrain intrinsic Hα luminosities corrected from nebular dust attenuation via Balmer decrements. We constrain dust-corrected UV luminosities from best-fit spectral energy distribution modeling. We find a sample median log 10 ( ξ ion,0 / erg Hz − 1 ) = 25.2 9 − 0.37 + 0.29 , assuming fesc = 0 for the escape fraction of Lyman continuum (LyC) emission. We find significant (Spearman rs = 0.19, p = 0.01) correlation between ξion,0 and z, with objects at z > 4.64 having median log 10 ( ξ ion,0 / erg Hz − 1 ) = 25.3 8 − 0.38 + 0.38 , with those below having log 10 ( ξ ion,0 / erg Hz − 1 ) = 25.2 4 − 0.33 + 0.30 . We also find significant, positive correlations between ξion,0 and LUV; Wλ([O iii]); [O iii]λ5007/[O ii]λλ3726, 3729; and inverse correlations with metallicity. In contrast with some previous results, we find no trends between ξion,0 and stellar mass, stellar dust attenuation, or UV slope. Applying a multivariate fit to ξion,0, z, and MUV to an empirically motivated model of reionization, and folding in fesc estimates from direct observations of the LyC at z ∼ 3 from the Keck Lyman Continuum Spectroscopic Survey, we find that the number of ionizing photons entering the IGM causes reionization to end at z ∼ 5-7.
AB - We have used a combined sample of JADES and CEERS objects in order to constrain ionizing photon production efficiency (ξion) from JWST/NIRSpec and JWST/NIRCam data. We examine 163 objects at 1.06 < z < 6.71 with significant (3σ) spectroscopic detections of Hα and Hβ in order to constrain intrinsic Hα luminosities corrected from nebular dust attenuation via Balmer decrements. We constrain dust-corrected UV luminosities from best-fit spectral energy distribution modeling. We find a sample median log 10 ( ξ ion,0 / erg Hz − 1 ) = 25.2 9 − 0.37 + 0.29 , assuming fesc = 0 for the escape fraction of Lyman continuum (LyC) emission. We find significant (Spearman rs = 0.19, p = 0.01) correlation between ξion,0 and z, with objects at z > 4.64 having median log 10 ( ξ ion,0 / erg Hz − 1 ) = 25.3 8 − 0.38 + 0.38 , with those below having log 10 ( ξ ion,0 / erg Hz − 1 ) = 25.2 4 − 0.33 + 0.30 . We also find significant, positive correlations between ξion,0 and LUV; Wλ([O iii]); [O iii]λ5007/[O ii]λλ3726, 3729; and inverse correlations with metallicity. In contrast with some previous results, we find no trends between ξion,0 and stellar mass, stellar dust attenuation, or UV slope. Applying a multivariate fit to ξion,0, z, and MUV to an empirically motivated model of reionization, and folding in fesc estimates from direct observations of the LyC at z ∼ 3 from the Keck Lyman Continuum Spectroscopic Survey, we find that the number of ionizing photons entering the IGM causes reionization to end at z ∼ 5-7.
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U2 - 10.3847/1538-4357/adb1ab
DO - 10.3847/1538-4357/adb1ab
M3 - Article
AN - SCOPUS:86000320139
SN - 0004-637X
VL - 981
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 134
ER -