Are evolving dark energy hints driven by supernova systematics? · revision history

Revision 2

Accepted · core change · record

Changes against revision 1:

Title
Are evolving dark energy hints driven by supernova systematics?
Plain
Exploding stars called type Ia supernovae serve as distance markers, and the dark energy hint depends on which supernova catalog is used. Small calibration errors between nearby and distant supernovae could fake the signal.
Precise · changed · core
Revision 1: The DESI DR2 preference for $w0-wa$ ranges from about $2.8\text{ to }4.2\sigma$ across Pantheon+, Union3 and DES-Y5, and the 2025 DES reanalysis (Dovekie) lowered the DES value. Determine whether a distance-modulus offset of order 0.04 mag between low-redshift ($z < 0.1$) and high-redshift supernovae, from photometric calibration, selection, or host-galaxy dust and age evolution, accounts for the signal. Answer: identification of such a systematic or a demonstration that all such offsets are below $0.01\,\mathrm{mag}$.
Revision 2: The DESI DR2 preference for $w0-wa$ ranges from about $2.8\text{ to }4.2\sigma$ across Pantheon+, Union3 and DES-Y5, and the 2025 DES reanalysis (Dovekie) lowered the DES value. Determine whether a distance-modulus offset of order $0.04\,\mathrm{mag}$ between low-redshift ($z < 0.1$) and high-redshift supernovae, from photometric calibration, selection, or host-galaxy dust and age evolution, accounts for the signal. Answer: identification of such a systematic or a demonstration that all such offsets are below $0.01\,\mathrm{mag}$.
Settled by
A single-survey supernova sample spanning $0 < z < 1$ on one photometric system, cross-checked against BAO-only and CMB-only fits.
Kind
well-posed
Answer type
identification
References
(empty)
Literature status
contested
Status note
The 2025 DES-Dovekie recalibration reduced the preference from 4.2 to about $3.2\sigma$ with DESI DR2 and CMB.
Posed since
2025

Decisions