Still non-accelerating: age-bias correction in supernova cosmology is robust to host-progenitor age mapping
Abstract
We re-examine the claim by Wiseman et al. (2026) that progenitor-age bias has a negligible impact on cosmological inferences from Type Ia supernovae (SNe Ia). We show that their inferred host-age-Hubble residual (HR) slope is severely underestimated because their combined SN Ia sample spans an unusually wide redshift range (0.04 < z < 0.42), over which the mean host age evolves by ∼\,3 Gyr. As a result, SNe Ia spanning substantial host-age differences are effectively assigned similar HR values prior to regression, artificially flattening the inferred age-HR relation. In addition, their application of the Pantheon+ host-mass correction further suppresses the slope, but the underlying dust model is highly incompatible with the measured dust attenuation curves of galaxies. We also demonstrate that our age bias correction is robust to uncertainties in host-progenitor age mapping arising from different choices of the SN Ia delay-time distribution. The reduced progenitor-age evolution argued by Wiseman et al. (2026) must, by the same logic, be accompanied by a steeper inferred progenitor-age-HR slope. When these two effects are consistently combined in computing the redshift-dependent magnitude correction, the final correction, and hence the resulting cosmological impact, remain largely unchanged from Son et al. (2025).
Versions
Related
- A three-dimensional exploration of magnetic fields, rotation, and shock revival in a 39 M⊙ core-collapse supernova progenitor
- Type Ia supernova population machine – I. A unified cosmological simulation–binary synthesis framework establishing non-universal delay-time distributions and cosmic progenitor-channel dominance crossover
- Flavor Conversion Enhances or Suppresses Supernova Explodability Independent of the Progenitor Mass
- Structure of Convective-Reactive Zone in a Supernova Progenitor
- SN 2021pfs: A Type Ia Supernova Likely Affected by Progenitor Metallicity, as Revealed by Comparison with Its Twin Counterpart
BibTeX
@misc{chung2026still,
title = {{Still non-accelerating: age-bias correction in supernova cosmology is robust to host-progenitor age mapping}},
author = {Chul Chung and Junhyuk Son and Seunghyun Park and Suk-Jin Yoon and Hyejeon Cho and Dongwook Lim and Young-Wook Lee},
howpublished = {arXiv},
year = {2026},
month = may,
doi = {10.48550/arxiv.2605.21586},
eprint = {2605.21586},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.21586},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Still non-accelerating: age-bias correction in supernova cosmology is robust to host-progenitor age mapping
AU - Chul Chung
AU - Junhyuk Son
AU - Seunghyun Park
AU - Suk-Jin Yoon
AU - Hyejeon Cho
AU - Dongwook Lim
AU - Young-Wook Lee
PY - 2026
DA - 2026/05/20
PB - arXiv
DO - 10.48550/arxiv.2605.21586
UR - https://arxiv.org/abs/2605.21586
AB - We re-examine the claim by Wiseman et al. (2026) that progenitor-age bias has a negligible impact on cosmological inferences from Type Ia supernovae (SNe Ia). We show that their inferred host-age-Hubble residual (HR) slope is severely underestimated because their combined SN Ia sample spans an unusually wide redshift range (0.04 < z < 0.42), over which the mean host age evolves by ∼\,3 Gyr. As a result, SNe Ia spanning substantial host-age differences are effectively assigned similar HR values prior to regression, artificially flattening the inferred age-HR relation. In addition, their application of the Pantheon+ host-mass correction further suppresses the slope, but the underlying dust model is highly incompatible with the measured dust attenuation curves of galaxies. We also demonstrate that our age bias correction is robust to uncertainties in host-progenitor age mapping arising from different choices of the SN Ia delay-time distribution. The reduced progenitor-age evolution argued by Wiseman et al. (2026) must, by the same logic, be accompanied by a steeper inferred progenitor-age-HR slope. When these two effects are consistently combined in computing the redshift-dependent magnitude correction, the final correction, and hence the resulting cosmological impact, remain largely unchanged from Son et al. (2025).
ER -