A Truncation Test of the DESI Evolving Dark Energy Signal: Three Supernova Calibrations Compared

Clicks: 1
ID: 330692
2026
Free PDF
Article Quality & Performance Metrics
Overall Quality
Not rated
Combines reader engagement with the AI quality analysis. This article has not been analysed, so there is no overall score — reader engagement is measured and shown alongside.
AI Quality Assessment
Not analyzed
Readership in this journal

Ranked #1,120 of 1,125 articles by views in monthly notices of the royal astronomical society

Most read Least read

Bar heights use a square-root scale. Only the 120 most-read articles are drawn; the journal has 1,125 in total.

Mint this article as an NFT
Not yet minted

Create a permanent, verifiable on-chain record of this article on the Scimatic Network. The NFT is held in your Journament account, and you can withdraw it to your own wallet at any time.

5 SUSD one-off · no wallet required
Sign in to mint
Abstract
Abstract The DESI DR2 collaboration reported ∼4σ evidence for evolving dark energy (w0 > −1, wa < 0) from baryon acoustic oscillations (BAO) combined with Type Ia supernova (SN Ia) distances. A persistent concern is whether low-redshift SN calibration systematics drive this signal. We introduce a redshift truncation scan—progressively excising low-z SNe and re-fitting CPL cosmology—and apply it to three SN datasets with independent absolute calibrations: Pantheon+ (SH0ES Cepheid distance ladder), DESY5 (internal BAO-anchored calibration), and DES-Dovekie (white dwarf SEDs + Gaia spectrophotometry). All chains use the full Planck 2018 TTTEEE_lite likelihood. We show that the signal is not dominated by photometric calibration. DES-Dovekie serves as a positive control: its CPL signal, already weakened by the recalibration, collapses under truncation—the signature of a calibration-driven signal. In contrast, Pantheon+ and DESY5 retain a ∼2σ deviation (Δχ2 ≈ 4) after all z ≤ 0.12 SNe are removed that does not weaken with further truncation. Quantitatively, in χ2 space the signal decomposes into photometric calibration (Δχ2 = 7.6, 2.8σ) and low-z non-calibration (Δχ2 = 7.4, 2.7σ), which together with a residual consistent with the CMB+BAO baseline (Δχ2 ≈ 2, 1.4σ) reproduce the DESY5 total (4.0σ) to within a few percent. This truncation-immune residual is either genuine dark energy evolution or a shared SN Ia standardization systematic beyond calibration.
Reference Key
openalex_W7214923101 Use this key to autocite in the manuscript while using SciMatic Manuscript Manager or Thesis Manager
Authors Tao Zhang
Journal monthly notices of the royal astronomical society
Year 2026
DOI
10.1093/mnras/stag1868
URL
https://doi.org/10.1093/mnras/stag1868
Keywords Keywords not found

Citations

No citations found. To add a citation, contact the admin at info@scimatic.org

Comments

No comments yet. Be the first to comment on this article.