Pith. sign in

REVIEW 3 major objections 6 minor 80 references

Reviewed by Pith at T0; open to challenge.

T0 means a machine referee read the full paper against a public rubric. The mark states how deep the mechanical check went, never who wrote it. the ladder, T0–T4 →

T0 review · glm-5.2

DESI's Non-Accelerating Universe May Be a Redshift Gap, Not New Physics

2026-07-09 13:27 UTC pith:XBBRLRLH

load-bearing objection DESI's positive q0 from BAO+CMB is likely a redshift-coverage artifact, but the comparison is confounded by mismatched pipelines the 3 major comments →

arxiv 2607.07348 v1 pith:XBBRLRLH submitted 2026-07-08 astro-ph.CO

Present Day Cosmic Acceleration from SDSS and DESI BAO: A Call for Finer Tomography of the DESI Bright Galaxy Survey

classification astro-ph.CO
keywords cosmic accelerationdeceleration parameterbaryon acoustic oscillationsDESISDSSdark energyCPL parametrizationredshift sampling
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This paper argues that the apparent preference of DESI DR2 baryon acoustic oscillation data, when combined with CMB measurements, for a presently non-accelerating Universe is not evidence for exotic dark energy but a consequence of redshift sampling. DESI's lowest effective redshift bin sits at z_eff ≈ 0.295, while SDSS reaches down to z_eff ≈ 0.15. Because the present-day equation of state w_0 and the deceleration parameter q_0 are quantities defined at z = 0, the absence of a distance anchor close to the present epoch forces the CPL dark energy parametrization to extrapolate, allowing w_0 to drift toward zero and q_0 to become positive. The authors support this with two tests: adding Pantheon+ supernovae (which reach lower redshifts) to DESI restores q_0 to −0.37, and removing SDSS's low-redshift anchor shifts SDSS's q_0 from −0.22 toward −0.10, intermediate between the two surveys. They propose finer tomographic binning of DESI's Bright Galaxy Survey to access lower effective redshifts and test the conclusion.

Core claim

The discrepancy between DESI and SDSS on whether the Universe is currently accelerating is driven by the ~0.15 difference in their lowest effective redshift anchors (z_eff ≈ 0.295 for DESI vs. z_eff ≈ 0.15 for SDSS). In the CPL parametrization, w_0 and q_0 are present-day quantities that require low-redshift data to constrain directly; without such an anchor, the reconstruction extrapolates and q_0 drifts positive. Two tests confirm this: adding Pantheon+ supernovae to DESI restores acceleration (q_0 = −0.37), and removing SDSS's low-z MGS anchor shifts SDSS's q_0 from −0.22 toward −0.10.

What carries the argument

The deceleration parameter q_0 = (1/2)Ω_m + (1/2)(1 + 3w_0)Ω_DE, which depends only on the present-day equation of state w_0 and energy densities. Within the CPL parametrization, w_0 is the parameter most directly tied to the lowest-redshift expansion history. A distance anchor at z_eff ≈ 0.15 constrains w_0 directly; an anchor at z_eff ≈ 0.295 forces extrapolation to z = 0, allowing w_0 to drift toward zero and pushing q_0 across the acceleration boundary.

Load-bearing premise

The comparison between DESI and SDSS chains is not apples-to-apples: the CMB likelihood versions differ (Plik vs. NPIPE CamSpec), the lensing datasets differ (Planck 2018 vs. Planck+ACT DR6), and the SDSS chains include redshift-space distortion (growth) information while the DESI BAO chains do not. The authors acknowledge this but attribute the q_0 shift to redshift coverage; if these dataset differences contribute non-negligibly, the redshift-sampling explanation is overst.

What would settle it

If finer tomographic binning of DESI's Bright Galaxy Survey at z_eff ~ 0.18 does not pull q_0 back toward negative values, or if a matched-likelihood reanalysis (identical CMB, BAO-only, no RSD) eliminates the q_0 shift between surveys, the redshift-sampling explanation would be weakened or falsified.

Watch this falsifier — get emailed when new claim-graph text bears on it.

If this is right

  • If finer tomographic binning of DESI's Bright Galaxy Survey can achieve an effective redshift of ~0.18, it would provide a direct test: a low-z BGS bin should pull q_0 back toward negative values, consistent with SDSS and ΛCDM.
  • The result suggests that the significance of dynamical dark energy claims from BAO+CMB combinations without low-redshift supernova anchors should be treated cautiously, as they depend on extrapolation within the chosen parametrization.
  • The finding motivates a matched-likelihood reanalysis (identical CMB likelihoods, BAO-only without RSD) to isolate the pure geometric contribution of redshift coverage versus other dataset differences.
  • If the redshift-sampling explanation is correct, future DESI data releases with finer low-z binning should show reduced tension with ΛCDM in the w_0–q_0 plane even without supernovae.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The argument implies that the choice of dark energy parametrization itself matters: CPL extrapolates differently from, say, early dark energy or thawing quintessence models. A parametrization that changes more slowly at low redshift might show a smaller q_0 shift, suggesting the 'non-accelerating' result is partly an artifact of how CPL extrapolates into the unconstrained region.
  • The same redshift-coverage logic could apply to other present-day cosmological quantities derived from BAO+CMB combinations, such as H_0 or σ_8, potentially explaining other apparent tensions between DESI and earlier surveys.
  • If the proposed BGS tomographic split fails to restore acceleration, this would weaken the redshift-sampling explanation and reopen the possibility that the DESI BAO+CMB preference genuinely reflects the expansion history rather than an extrapolation artifact.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

3 major / 6 minor

Summary. This manuscript compares the inference of the present-day deceleration parameter q0 from SDSS DR16 and DESI DR2 BAO data, both combined with Planck CMB, within the CPL (w0wa) dark energy parametrization. The central observation is that Planck+DESI yields q0 = +0.10 (median on the decelerating side), while Planck+SDSS yields q0 = -0.22 (accelerating). The authors attribute this difference to the gap in lowest effective redshift probed (z_eff ≈ 0.295 for DESI BGS vs. z_eff ≈ 0.15 for SDSS MGS), arguing that the DESI result reflects extrapolation rather than new physics. Two tests support this: adding Pantheon+ to DESI restores q0 ≈ -0.37, and removing the MGS anchor from SDSS shifts q0 from -0.22 toward -0.10. The paper concludes with a recommendation for finer tomographic binning of the DESI BGS sample.

Significance. The paper addresses a timely question: whether the DESI BAO+CMB hint of a non-accelerating present epoch is physically meaningful or an artifact of redshift sampling. The use of the parameter-free identity q0 = 1/2 Omega_m + 1/2(1+3w0)Omega_DE (Eq. 11) to compute q0 from MCMC posteriors is methodologically sound and avoids circularity. The two confirmatory tests (Pantheon+ addition, MGS removal) are well-designed and behave as predicted. The recommendation for finer BGS tomography is a concrete, falsifiable proposal. However, the quantitative force of the comparison is limited by acknowledged pipeline mismatches between the SDSS and DESI chains.

major comments (3)
  1. §4, caveat paragraph and §6.2.3: The SDSS chains (base_w_wa_CMBLens_BAORSD) include RSD (growth) information, while the DESI BAO chains do not. In the CPL model, RSD constrains fσ8, which depends on the integrated growth history and thus on w(z) including wa. This can shift the posterior along the w0–wa degeneracy direction, indirectly moving w0 and therefore q0. The MGS-removal test (§6.2.3) removes the low-z BAO anchor but retains RSD and the 2018-era CMB likelihood, so the residual offset between MGS-removed SDSS (q0 = -0.10) and DESI (q0 = +0.10) could be partly or entirely due to RSD and pipeline differences rather than 'remaining differences in redshift sampling and survey geometry' as stated. The authors note that BAO-only SDSS chains are publicly available and would isolate the geometric contribution, but state 'We attempt neither here.' This is the single most important gap: the
  2. §5.1, Eqs. (14)–(15): The w0 offset between SDSS and DESI is ~0.30, corresponding to only ~1.1σ when treated as independent. The authors acknowledge this is 'a marginal, not a decisive, difference' and correctly note that shared Planck information makes the posteriors positively correlated, so 1.1σ is conservative. However, the abstract and conclusions frame q0 = +0.10 vs. q0 = -0.22 as a 'qualitative discrepancy' and a 'key result.' Given that both intervals are consistent with q0 = 0 at roughly 1σ, the framing overstates the statistical significance of the contrast. The paper should more clearly state in the abstract and conclusions that the difference is ~1.1σ and that the 'qualitative' framing refers to the sign of the median, not to a statistically significant tension.
  3. §4.1 vs. §4.4: The Planck-only chains use Plik TTTEEE lite + 2018 lensing, the DESI chains use NPIPE CamSpec + Planck/ACT DR6 lensing, and the SDSS chains use 2018-era likelihoods. The authors state these differences are 'subdominant' but provide no quantitative justification. Even a rough estimate of the expected q0 shift from switching CMB likelihoods (e.g., comparing Planck-only results under Plik vs. NPIPE) would strengthen the claim that the BAO redshift coverage is the dominant driver. Without this, the attribution to redshift sampling alone remains unquantified.
minor comments (6)
  1. Table 1: The Planck-only wCDM row reports w0 = -1.59 and q0 = -1.44, which are far from ΛCDM values. While the uncertainties are large, these median values seem extreme; a brief comment on why Planck-only wCDM prefers such a phantom-like value would help the reader.
  2. §6.2.1: The double transition redshift z_crit = {0.08, 0.86} for Planck+DESI is noted as arising from 'near-tangency of q(z) with zero.' It would help to show q(z) crossing zero twice in Fig. 1 (right panel) or a dedicated inset, as this is a striking qualitative claim.
  3. Fig. 2 caption: The caption states the accelerating region is 'to the left of the curve' (more negative w0), but the q0 = 0 boundary (Eq. 12) has w0 = -1/(3Ω_DE), which becomes more negative as Ω_DE decreases. A reader might find it confusing which direction is 'left'; consider labeling the regions directly on the figure.
  4. §6.2.3, Eq. (19): The MGS-removed SDSS result has q0 = -0.10 ± 0.33/0.35, which is consistent with both DESI's q0 = +0.10 and the full SDSS q0 = -0.22. The text describes this as 'intermediate,' which is true for the median, but the uncertainty is so large that the test is only weakly constraining. This should be stated more explicitly.
  5. The reference list includes several 2026-dated arXiv entries (e.g., Ref. [17, 18, 41, 75]); ensure these are correctly cited and that journal references are finalized where applicable.
  6. §3, Eq. (10): The notation switches between Ω_DE and Ω_DE,0; consider standardizing to one form throughout.

Simulated Author's Rebuttal

3 responses · 1 unresolved

We thank the referee for a careful and constructive report. The referee raises three major points: (1) the SDSS chains include RSD information while the DESI chains do not, and a BAO-only SDSS comparison would isolate the geometric contribution; (2) the ~1.1σ statistical significance of the w0 and q0 differences is understated in the abstract and conclusions; and (3) the claim that CMB likelihood differences are subdominant lacks quantitative justification. We address each point below and describe the revisions we will make.

read point-by-point responses
  1. Referee: §4, caveat paragraph and §6.2.3: The SDSS chains include RSD (growth) information while DESI BAO chains do not. RSD constrains fσ8, which depends on the integrated growth history and thus on w(z) including wa, potentially shifting the posterior along the w0–wa degeneracy direction. The MGS-removal test retains RSD and 2018-era CMB, so the residual offset between MGS-removed SDSS (q0 = -0.10) and DESI (q0 = +0.10) could be partly or entirely due to RSD and pipeline differences. The BAO-only SDSS chains are publicly available and would isolate the geometric contribution, but the authors state 'We attempt neither here.' This is the single most important gap.

    Authors: The referee is correct that the inclusion of RSD in the SDSS chains and its absence from the DESI BAO chains is a confounding factor, and that the BAO-only SDSS chains would provide a cleaner comparison. We agree this is the most important methodological gap in the current manuscript. We will address it in revision by running the BAO-only (no-RSD) SDSS DR16 chains, which are publicly available in the same repository we already use, and reporting the resulting q0 and w0 values alongside the existing results. This will directly isolate the geometric BAO contribution and allow us to assess how much of the SDSS–DESI offset persists when RSD is removed from the SDSS side. We will revise the manuscript accordingly, including updating Table 1 and the discussion in §6.2.3. We acknowledge that even after removing RSD, the CMB likelihood differences (Plik vs. NPIPE CamSpec, 2018 lensing vs. Planck+ACT DR6 lensing) will remain as a residual confounder; we address this in our response to the third comment below. We will also revise the language in §6.2.3 to avoid attributing the residual offset solely to 'remaining differences in redshift sampling and survey geometry' and will instead enumerate the RSD and CMB pipeline differences as additional possible contributors. revision: yes

  2. Referee: §5.1, Eqs. (14)–(15): The w0 offset between SDSS and DESI is ~0.30, corresponding to only ~1.1σ when treated as independent. The abstract and conclusions frame q0 = +0.10 vs. q0 = -0.22 as a 'qualitative discrepancy' and a 'key result.' Given that both intervals are consistent with q0 = 0 at roughly 1σ, the framing overstates the statistical significance of the contrast. The paper should more clearly state in the abstract and conclusions that the difference is ~1.1σ and that the 'qualitative' framing refers to the sign of the median, not to a statistically significant tension.

    Authors: The referee is correct. The ~1.1σ significance of the w0 (and q0) offset is already stated in §5.1, but the abstract and conclusions do not convey this clearly enough and could be read as implying a statistically significant tension. We will revise the abstract to explicitly note that the w0 and q0 differences correspond to approximately 1.1σ and that the 'qualitative discrepancy' refers to the sign of the posterior median (one positive, one negative), not to a statistically significant tension. We will make the corresponding revision in the conclusions (§7). The core argument of the paper—that the sign of the median q0 is sensitive to the lowest effective redshift probed, and that this sensitivity is demonstrated by the Pantheon+ addition and MGS-removal tests—does not depend on the difference being statistically significant, so this revision does not undermine the paper's thesis. Rather, it clarifies that we are reporting a directional trend supported by two confirmatory tests, not a detection of tension. revision: yes

  3. Referee: §4.1 vs. §4.4: The Planck-only chains use Plik TTTEEE lite + 2018 lensing, the DESI chains use NPIPE CamSpec + Planck/ACT DR6 lensing, and the SDSS chains use 2018-era likelihoods. The authors state these differences are 'subdominant' but provide no quantitative justification. Even a rough estimate of the expected q0 shift from switching CMB likelihoods would strengthen the claim that BAO redshift coverage is the dominant driver.

    Authors: The referee is right that the claim that CMB likelihood differences are 'subdominant' is currently unsupported by any quantitative estimate. We can partially address this: our independently run Planck-only chains (§4.1, Table 1) use Plik TTTEEE lite + 2018 lensing and yield q0 = -0.83 with very broad uncertainties in CPL. The DESI collaboration's own Planck-only chains using NPIPE CamSpec + Planck/ACT DR6 lensing are publicly available, and we can compute q0 from them using the same identity (Eq. 11). Comparing these two Planck-only results would give a direct, if rough, estimate of the q0 shift attributable to the CMB likelihood and lensing change alone. We will add this comparison to the revised manuscript. However, we want to be transparent about a limitation: because the Planck-only posteriors in CPL are extremely broad (the q0 uncertainty is ~0.8), the shift between Plik and NPIPE CamSpec may itself be poorly determined, and we may not be able to make a precise statement about its magnitude. If the shift is small compared to the BAO-driven shift (as we expect but must verify), this will support our argument; if it is not, we will revise our claim accordingly. In either case, we will remove the unsupported word 'subdominant' and replace it with the quantitative comparison. revision: partial

standing simulated objections not resolved
  • We cannot fully eliminate the CMB likelihood confounding without re-running all chains with a single, matched CMB+lensing likelihood. Our Planck-only chains use Plik + 2018 lensing, while the DESI public chains use NPIPE CamSpec + Planck/ACT DR6 lensing, and the SDSS public chains use 2018-era likelihoods. Re-running the SDSS or DESI BAO with a matched CMB pipeline is beyond the scope of what we can accomplish with publicly released chains alone. The BAO-only SDSS comparison (committed to in response to comment 1) and the Planck-only Plik-vs-NPIPE comparison (committed to in response to comment 3) will reduce but not eliminate this confounding. We will be transparent about this residual limitation in the revised manuscript.

Circularity Check

0 steps flagged

No significant circularity: q0 is derived from a parameter-free identity applied to MCMC posteriors, and the two confirmatory tests are independent data manipulations.

full rationale

The paper's central derivation chain is self-contained. The deceleration parameter q0 is computed from the standard identity q0 = 1/2 Omega_m + 1/2(1+3w0)Omega_DE (Eq. 11), which is a parameter-free algebraic relation applied to MCMC posterior samples of (w0, Omega_DE). No parameter is fitted to q0 and then used to predict q0. The two confirmatory tests—adding Pantheon+ to DESI and removing the MGS anchor from SDSS—are independent manipulations of the data combinations, not re-derivations from fitted parameters. The paper uses publicly released external chains (DESI DR2, SDSS DR16) and its own Planck-only MCMC runs, so the inputs are externally sourced. The only minor concern is that the SDSS chains include RSD information while DESI BAO chains do not, and the CMB likelihood versions differ, which the authors acknowledge in the Sec. 4 caveat. This is a confound risk (correctness concern), not circularity: the paper does not define a quantity in terms of itself, fit a parameter to a target and call the result a prediction, or invoke a self-citation chain as load-bearing evidence. The directional claim that the q0 difference reflects redshift sampling is supported by the MGS-removal test showing an intermediate q0 value, which is an independent data manipulation rather than a tautological re-derivation. No step in the derivation chain reduces to its inputs by construction.

Axiom & Free-Parameter Ledger

5 free parameters · 4 axioms · 0 invented entities

The paper introduces no new particles, forces, dimensions, or postulated entities. All free parameters (w0, wa, Omega_m, h0, Sum m_nu) are standard cosmological parameters fitted via MCMC to public data. The axioms are standard cosmological assumptions (FLRW, flatness, CPL) plus the ad-hoc-to-paper assumption that the mismatched chains are comparable. The main risk is the last axiom: if the CMB likelihood and RSD differences between the SDSS and DESI chains contribute significantly to the q0 shift, the central claim is weakened.

free parameters (5)
  • w0 = varies by dataset (e.g., -0.41 for DESI+CMB, -0.71 for SDSS+CMB)
    Present-day dark energy equation of state, fitted via MCMC to BAO+CMB data in the CPL parametrization.
  • wa = varies by dataset (e.g., -1.78 for DESI+CMB, -0.94 for SDSS+CMB)
    CPL evolution parameter, fitted via MCMC. Does not enter q0 directly but affects the distance-redshift relation.
  • Omega_m,0 = varies by dataset (e.g., 0.35 for DESI+CMB, 0.33 for SDSS+CMB)
    Present-day matter density fraction, fitted via MCMC. Enters q0 through Eq. 11.
  • h0 = varies by dataset
    Hubble constant, fitted as nuisance parameter in MCMC chains.
  • Sum m_nu = varies (e.g., 0.02 eV for DESI+CMB in nuCDM)
    Neutrino mass sum, varied in the nuCDM and wCDM+m_nu comparison models.
axioms (4)
  • domain assumption Spatial flatness (Omega_m + Omega_DE = 1)
    Used to simplify q0 in Eq. 11 and throughout the analysis. Standard in DESI and SDSS analyses but not independently tested here.
  • domain assumption CPL parametrization w(a) = w0 + wa(1-a) adequately describes dark energy evolution
    The entire analysis is conducted within this parametrization (Sec. 2). The authors note they plan to test other parametrizations in future work (Sec. 2).
  • standard math FLRW metric describes the Universe on large scales
    Underlies the Friedmann equations used throughout (Sec. 2, Eq. 1-4).
  • ad hoc to paper The publicly released SDSS and DESI MCMC chains are comparable despite different CMB likelihoods, lensing datasets, and RSD inclusion
    The paper's central comparison depends on this, but the authors themselves flag it as a caveat (Sec. 4) and state they 'attempt neither' the matched-likelihood nor BAO-only reanalysis.

pith-pipeline@v1.1.0-glm · 25055 in / 3517 out tokens · 396369 ms · 2026-07-09T13:27:41.306787+00:00 · methodology

0 comments
read the original abstract

The DESI collaboration's Data Release~2 (DR2) provides baryon acoustic oscillation (BAO) measurements from over 14 million galaxies and quasars, and a joint analysis of DESI BAO, CMB, and Type~Ia Supernovae reveals a preference for time-evolving dark energy. We quantify this preference relative to SDSS BAO and report three key results. First, DESI+Planck favors a higher $w_0 = -0.41^{+0.21}_{-0.22}$ than SDSS+Planck ($w_0 = -0.71^{+0.19}_{-0.18}$). Second, DESI+Planck prefers a deceleration parameter whose median lies on the decelerating side ($q_0 = 0.10^{+0.21}_{-0.23}$, consistent with $q_0 = 0$ at $1\sigma$), while SDSS+Planck prefers a negative value ($q_0 =-0.22^{+0.20}_{-0.21}$) indicating accelerated expansion. Third, we argue that this discrepancy arises from the difference in the lowest effective redshift probed by each survey: $z_{\rm eff} \approx 0.295$ for DESI versus $z_{\rm eff} \approx 0.15$ for SDSS. As present-day quantities, $w_0$ and $q_0$ are sensitive to the lowest probed redshift: data near $z = 0$ constrain them directly, whereas higher-redshift data rely on extrapolating the dark energy parametrization (here CPL). Reaching $z_{\rm eff} \approx 0.15$, SDSS constrains $w_0$ and $q_0$ in a data-driven way, finding consistency with $w_0 = -1$ and acceleration. Limited to $z_{\rm eff} \gtrsim 0.295$, DESI relies more on extrapolation, driving $q_0$ positive and $w_0$ well above $-1$. Adding the Pantheon+ supernova sample restores low-redshift information, returning $q_0$ to negative values and reducing tension with $\Lambda\text{CDM}$. We therefore propose that the apparent DESI preference for a non-accelerating present epoch in the BAO+CMB combination reflects redshift sampling rather than new physics, and suggest future DESI analyses adopt finer tomographic binning of the Bright Galaxy Survey sample to access lower mean redshifts and test this conclusion.

Figures

Figures reproduced from arXiv: 2607.07348 by Alessandro Melchiorri, Anna Chiara Ferri, Ruchika.

Figure 1
Figure 1. Figure 1: Comparison of the equation of state w(z) (left) and the deceleration parameter q(z) (right) across the different models considered for the two main BAO combinations. Four models are shown: w0waCDM (red), wCDM (blue), νCDM (ΛCDM + Pmν) (pink), and wCDM + Pmν (green). Planck+DESI is shown with continuous lines and Planck+SDSS with dashed lines. The black vertical lines indicate the smallest effective redshif… view at source ↗
Figure 2
Figure 2. Figure 2: Two-dimensional posterior distribution in the [PITH_FULL_IMAGE:figures/full_fig_p008_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Marginalized posteriors in the (w0, wa) plane for three data combinations. Left: using the full SDSS DR16 sample. Right: with the low redshift MGS anchor removed. Switching the BAO dataset from SDSS to DESI shifts the contours away from the cosmological-constant point (w0, wa) = (−1, 0), while the further inclusion of Pantheon+ decreases tension with ΛCDM. Removing the MGS anchor (right) broadens the SDSS … view at source ↗
Figure 4
Figure 4. Figure 4: Comparison of the equation of state w(z) (left) and the deceleration parameter q(z) (right) across all dataset combinations, for the model w0waCDM. Planck in cyan, Planck+DESI in red, Planck+SDSS in blue, Planck+SDSS(z > 0.295) in green, Planck+DESI+Pantheon+ in magenta. The black dashed vertical line indicates the smallest effective redshift probed by the Planck+SDSS(z > 0.295) dataset, in which the low r… view at source ↗
Figure 5
Figure 5. Figure 5: Visualization of the BAO tracers in the redshift domain. Each point marks the effective redshift [PITH_FULL_IMAGE:figures/full_fig_p011_5.png] view at source ↗

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

80 extracted references · 80 canonical work pages · 65 internal anchors

  1. [1]

    DESI Collaboration, The DESI Experiment Part I: Science,Targeting, and Survey Design (2016).arXiv:1611.00036

  2. [2]

    DESI Collaboration, The DESI Experiment Part II: Instrument Design (2016).arXiv: 1611.00037

  3. [3]

    DESI Collaboration, Overview of the In- strumentation for the Dark Energy Spec- troscopic Instrument, Astron. J. 164 (5) (2022) 207.arXiv:2205.10939,doi:10. 3847/1538-3881/ac882b

  4. [4]

    D.J.Eisenstein, etal., DetectionoftheBaryon Acoustic Peak in the Large-Scale Correlation Function of SDSS Luminous Red Galaxies, Astrophys. J. 633 (2005) 560–574.arXiv: astro-ph/0501171,doi:10.1086/466512

  5. [5]

    The 2dF Galaxy Redshift Survey: Power-spectrum analysis of the final dataset and cosmological implications

    S. Cole, et al., The 2dF Galaxy Redshift Survey: Power-spectrum analysis of the final dataset and cosmological implications, Mon. Not. Roy. Astron. Soc. 362 (2005) 505–534. arXiv:astro-ph/0501174,doi:10.1111/j. 1365-2966.2005.09318.x

  6. [6]

    DESI 2024 VI: Cosmological Constraints from the Measurements of Baryon Acoustic Oscillations

    DESI Collaboration, DESI 2024 VI: Cosmo- logical Constraints from the Measurements of Baryon Acoustic Oscillations, JCAP 02 13 (2025) 021.arXiv:2404.03002,doi:10. 1088/1475-7516/2025/02/021

  7. [7]

    DESI Collaboration, DESI 2024 III: Baryon Acoustic Oscillations from Galaxies and Quasars (2024).arXiv:2404.03000

  8. [8]

    DESI Collaboration, DESI 2024 IV: Baryon Acoustic Oscillations from the Lyman Alpha Forest (2024).arXiv:2404.03001

  9. [9]

    Planck 2018 results. VI. Cosmological parameters

    N. Aghanim, et al., Planck 2018 results. VI. Cosmological parameters, Astron. Astrophys. 641 (2020) A6, [Erratum: Astron.Astrophys. 652, C4 (2021)].arXiv:1807.06209,doi:10. 1051/0004-6361/201833910

  10. [10]

    DESI Collaboration, DESI 2024: Constraints on Physics-Focused Aspects of Dark Energy using DESI DR1 BAO Data (2024).arXiv: 2405.13588

  11. [11]

    Chevallier, D

    M. Chevallier, D. Polarski, Accelerating uni- verses with scaling dark matter, Int. J. Mod. Phys. D 10 (2001) 213–224.arXiv:gr-qc/ 0009008,doi:10.1142/S0218271801000822

  12. [12]

    E. V. Linder, Exploring the expansion history of the universe, Phys. Rev. Lett. 90 (2003) 091301.arXiv:astro-ph/0208512,doi:10. 1103/PhysRevLett.90.091301

  13. [13]

    Scolnic, et al., The Pantheon+ Analysis: TheFullDataSetandLight-curveRelease, As- trophys

    D. Scolnic, et al., The Pantheon+ Analysis: TheFullDataSetandLight-curveRelease, As- trophys. J. 938 (2) (2022) 113.arXiv:2112. 03863,doi:10.3847/1538-4357/ac8b7a

  14. [14]

    The Pantheon+ Analysis: Cosmological Constraints

    D. Brout, et al., The Pantheon+ Analy- sis: Cosmological Constraints, Astrophys. J. 938 (2) (2022) 110.arXiv:2202.04077,doi: 10.3847/1538-4357/ac8e04

  15. [15]

    Union Through UNITY: Cosmology with 2,000 SNe Using a Unified Bayesian Framework

    D. Rubin, et al., Union Through UNITY: Cosmology with 2,000 SNe Using a Unified Bayesian Framework, Astrophys. J. 986 (2) (2025) 231.arXiv:2311.12098,doi:10. 3847/1538-4357/adc0a5

  16. [16]

    T. M. C. Abbott, et al., The Dark En- ergy Survey: Cosmology Results with∼1500 New High-redshift Type Ia Supernovae Using the Full 5 yr Data Set, Astrophys. J. Lett. 973 (1) (2024) L14.arXiv:2401.02929,doi: 10.3847/2041-8213/ad6f9f

  17. [17]

    DESI DR2 Results II: Measurements of Baryon Acoustic Oscillations and Cosmological Constraints

    M. Abdul Karim, et al., DESI DR2 results. II. Measurements of baryon acoustic oscilla- tions and cosmological constraints, Phys. Rev. D 112 (8) (2025) 083515.arXiv:2503.14738, doi:10.1103/tr6y-kpc6

  18. [18]

    DESI DR2 Results I: Baryon Acoustic Oscillations from the Lyman Alpha Forest

    M. Abdul Karim, et al., DESI DR2 results. I. Baryon acoustic oscillations from the Ly- man alpha forest, Phys. Rev. D 112 (8) (2025) 083514.arXiv:2503.14739,doi:10.1103/ 2wwn-xjm5

  19. [19]

    K. S. Dawson, et al., The Baryon Oscilla- tion Spectroscopic Survey of SDSS-III, As- tron. J. 145 (2013) 10.arXiv:1208.0022, doi:10.1088/0004-6256/145/1/10

  20. [20]

    The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological analysis of the DR12 galaxy sample

    S. Alam, et al., The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological analysis of the DR12 galaxy sample, Mon. Not. Roy. As- tron. Soc. 470 (3) (2017) 2617–2652.arXiv: 1607.03155,doi:10.1093/mnras/stx721

  21. [21]

    K. S. Dawson, et al., The SDSS-IV Ex- tended Baryon Oscillation Spectroscopic Sur- vey: Overview and Early Data, Astron. J. 151 (2016) 44.arXiv:1508.04473,doi:10.3847/ 0004-6256/151/2/44

  22. [22]

    D. G. York, et al., The Sloan Digital Sky Survey: Technical Summary, Astron. J. 120 (2000) 1579–1587.arXiv:astro-ph/0006396, doi:10.1086/301513

  23. [24]

    J. E. Bautista, et al., The Completed SDSS- IV extended Baryon Oscillation Spectroscopic Survey: BAO and RSD measurements from the anisotropic correlation function of the lu- minous red galaxy sample (2020).arXiv: 2007.08993

  24. [25]

    A. de Mattia, et al., The Completed SDSS- IV extended Baryon Oscillation Spectroscopic Survey: BAO and RSD measurements from the anisotropic power spectrum of the emission line galaxy sample (2020).arXiv:2007.09008. 14

  25. [26]

    A. Tamone, et al., The Completed SDSS- IV extended Baryon Oscillation Spectroscopic Survey: Growth rate of structure measure- ment from the anisotropic correlation func- tion of the emission line galaxy sample (2020). arXiv:2007.09009

  26. [27]

    J. Hou, et al., The Completed SDSS-IV ex- tended Baryon Oscillation Spectroscopic Sur- vey: BAO and RSD measurements from the anisotropic clustering of the quasar sample (2020).arXiv:2007.08998

  27. [28]

    R. Neveux, et al., The Completed SDSS-IV ex- tended Baryon Oscillation Spectroscopic Sur- vey: BAO and RSD measurements from the anisotropic power spectrum of the quasar sam- plebetweenredshift0.8and2.2(2020).arXiv: 2007.08999

  28. [29]

    H. du Mas des Bourboux, et al., The Com- pleted SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Baryon acoustic oscilla- tions with Lyman-alpha forests (2020).arXiv: 2007.08995

  29. [30]

    Ruchika, 2D BAO vs 3D BAO: Hints for new physics?, Phys. Rev. D 112 (6) (2025) 063503.arXiv:2406.05453,doi:10.1103/ 9rt7-ph33

  30. [31]

    The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics

    E. Di Valentino, et al., The CosmoVerse White Paper: Addressing observational ten- sions in cosmology with systematics and fun- damental physics, Phys. Dark Univ. 49 (2025) 101965.arXiv:2504.01669,doi:10.1016/j. dark.2025.101965

  31. [32]

    Dutta, A

    K. Dutta, A. Roy, Ruchika, A. A. Sen, M. M. Sheikh-Jabbari, Cosmology with low-redshift observations: No signal for new physics, Phys. Rev. D 100 (10) (2019) 103501.arXiv:1908. 07267,doi:10.1103/PhysRevD.100.103501

  32. [33]

    Model independent constraints on dark energy evolution from low-redshift observations

    S. Capozziello, Ruchika, A. A. Sen, Model in- dependent constraints on dark energy evolu- tion from low-redshift observations, Mon. Not. Roy. Astron. Soc. 484 (2019) 4484.arXiv: 1806.03943,doi:10.1093/mnras/stz176

  33. [34]

    Modified gravity interpretation of the evolving dark energy in light of DESI data

    A. Chudaykin, M. Kunz, Modified gravity in- terpretation of the evolving dark energy in light of DESI data, Phys. Rev. D 110 (12) (2024) 123524.arXiv:2407.02558,doi:10. 1103/PhysRevD.110.123524

  34. [35]

    E. O. Colgáin, S. Pourojaghi, M. M. Sheikh- Jabbari, Implications of DES 5YR SNe Dataset forΛCDM (2024).arXiv:2406. 06389

  35. [36]

    E. O. Colgáin, M. G. Dainotti, S. Capozziello, S. Pourojaghi, M. M. Sheikh-Jabbari, D. Sto- jkovic, Does DESI 2024 ConfirmΛCDM? (2024).arXiv:2404.08633

  36. [37]

    Mukherjee, A

    P. Mukherjee, A. A. Sen, Model-independent cosmological inference post DESI DR1 BAO measurements, Phys. Rev. D 110 (12) (2024) 123502.arXiv:2405.19178,doi:10.1103/ PhysRevD.110.123502

  37. [38]

    Interpreting DESI's evidence for evolving dark energy

    M. Cortês, A. R. Liddle, Interpreting DESI’s evidence for evolving dark energy, JCAP 12 (2024) 007.arXiv:2404.08056,doi:10. 1088/1475-7516/2024/12/007

  38. [39]

    Does dark energy really revive using DESI 2024 data?

    Y. Carloni, O. Luongo, M. Muccino, Does dark energy really revive using DESI 2024 data?, Phys. Rev. D 111 (2) (2025) 023512. arXiv:2404.12068,doi:10.1103/PhysRevD. 111.023512

  39. [40]

    Interacting Dark Energy after DESI Baryon Acoustic Oscillation measurements

    W. Giarè, M. A. Sabogal, R. C. Nunes, E. Di Valentino, Interacting Dark Energy af- ter DESI Baryon Acoustic Oscillation Mea- surements, Phys. Rev. Lett. 133 (25) (2024) 251003.arXiv:2404.15232,doi:10.1103/ PhysRevLett.133.251003

  40. [41]

    T. M. C. Abbott, et al., Constraints on Dynamical Dark Energy from Multiple Probes in the Full Dark Energy Survey (5 2026).arXiv:2605.27221,doi:10.48550/ arXiv.2605.27221

  41. [42]

    D. Wang, D. Mota, Did DESI DR2 truly re- veal dynamical dark energy?, Eur. Phys. J. C 85 (11) (2025) 1356.arXiv:2504.15222, doi:10.1140/epjc/s10052-025-15076-y

  42. [43]

    Constraining Cosmological Physics with DESI BAO Observations

    D. Wang, Constraining cosmological physics with DESI BAO observations (2024).arXiv: 2404.06796

  43. [44]

    Outliers in DESI BAO: robustness and cosmological implications

    D. Sapone, S. Nesseris, Outliers in DESI BAO: Robustness and cosmological implications, Phys. Rev. D 112 (6) (2025) 063523.arXiv: 2412.01740,doi:10.1103/yknm-xskb. 15

  44. [45]

    Efstathiou, Evolving dark energy or su- pernovae systematics? (2024).arXiv:2408

    G. Efstathiou, Evolving dark energy or su- pernovae systematics? (2024).arXiv:2408. 07175

  45. [46]

    S. M. Carroll, The cosmological constant, Liv- ing Rev. Rel. 4 (2001) 1.arXiv:astro-ph/ 0004075,doi:10.12942/lrr-2001-1

  46. [47]

    Dark Energy and the Accelerating Universe

    J. Frieman, M. Turner, D. Huterer, Dark energy and the accelerating universe, Ann. Rev. Astron. Astrophys. 46 (2008) 385–432. arXiv:0803.0982,doi:10.1146/annurev. astro.46.060407.145243

  47. [48]

    E. J. Copeland, M. Sami, S. Tsujikawa, Dy- namics of dark energy, Int. J. Mod. Phys. D 15 (2006) 1753–1936.arXiv:hep-th/0603057, doi:10.1142/S021827180600942X

  48. [49]

    R. R. Caldwell, M. Kamionkowski, The physics of cosmic acceleration, Ann. Rev. Nucl. Part. Sci. 59 (2009) 397–429.arXiv:0903.0866,doi: 10.1146/annurev-nucl-010709-151330

  49. [50]

    Cosmology and fundamental physics with the Euclid satellite

    L. Amendola, et al., Cosmology and Funda- mental Physics with the Euclid Satellite, Liv- ing Rev. Rel. 16 (2013) 6.arXiv:1206.1225, doi:10.12942/lrr-2013-6

  50. [51]

    R. R. Caldwell, E. V. Linder, The Limits of Quintessence, Phys. Rev. Lett. 95 (2005) 141301.arXiv:astro-ph/0505494,doi:10. 1103/PhysRevLett.95.141301

  51. [52]

    Two new diagnostics of dark energy

    V. Sahni, A. Shafieloo, A. A. Starobinsky, Two new diagnostics of dark energy, Phys. Rev. D 78 (2008) 103502.arXiv:0807.3548,doi:10. 1103/PhysRevD.78.103502

  52. [53]

    Hubble parameter measurement constraints on the redshift of the deceleration-acceleration transition, dynamical dark energy, and space curvature

    O. Farooq, F. Madiyar, S. Crandall, B. Ra- tra, Hubble parameter measurement con- straints on the redshift of the deceleration– accelerationtransition, dynamicaldarkenergy, and space curvature, Astrophys. J. 835 (1) (2017) 26.arXiv:1607.03537,doi:10.3847/ 1538-4357/835/1/26

  53. [54]

    Y. Wang, L. Pogosian, G.-B. Zhao, A. Zucca, Evolution of dark energy reconstructed from the latest observations, Astrophys. J. Lett. 869 (1) (2018) L8.arXiv:1807.03772,doi: 10.3847/2041-8213/aaf238

  54. [55]

    Massive neutrinos and cosmology

    J. Lesgourgues, S. Pastor, Massive neutri- nos and cosmology, Phys. Rept. 429 (2006) 307–379.arXiv:astro-ph/0603494,doi:10. 1016/j.physrep.2006.04.001

  55. [56]

    Neutrino masses and the dark energy equation of state - relaxing the cosmological neutrino mass bound

    S. Hannestad, Neutrino masses and the dark energy equation of state: Relaxing the cosmo- logical neutrino mass bound, Phys. Rev. Lett. 95 (2005) 221301.arXiv:astro-ph/0505551, doi:10.1103/PhysRevLett.95.221301

  56. [57]

    Unveiling $\nu$ secrets with cosmological data: neutrino masses and mass hierarchy

    S. Vagnozzi, E. Giusarma, O. Mena, K. Freese, M. Gerbino, S. Ho, M. Lattanzi, Unveiling νsecrets with cosmological data: neutrino masses and mass hierarchy, Phys. Rev. D 96 (12) (2017) 123503.arXiv:1701.08172, doi:10.1103/PhysRevD.96.123503

  57. [58]

    Status of neutrino properties and future prospects - Cosmological and astrophysical constraints

    M. Lattanzi, M. Gerbino, Status of neutrino properties and future prospects – Cosmological andastrophysicalconstraints, Front.inPhys.5 (2018) 70.arXiv:1712.07109,doi:10.3389/ fphy.2017.00070

  58. [59]

    Early Dark Energy Cosmologies

    M. Doran, G. Robbers, Early dark energy cosmologies, JCAP 06 (2006) 026.arXiv:astro-ph/0601544,doi: 10.1088/1475-7516/2006/06/026

  59. [60]

    G.-B. Zhao, M. Raveri, L. Pogosian, Y. Wang, R. G. Crittenden, et al., Dynamical dark en- ergy in light of the latest observations, Nature Astron. 1 (2017) 627–632.arXiv:1701.08165, doi:10.1038/s41550-017-0216-z

  60. [61]

    Model independent evidence for dark energy evolution from Baryon Acoustic Oscillations

    V. Sahni, A. Shafieloo, A. A. Starobinsky, Model independent evidence for dark energy evolution from Baryon Acoustic Oscillations, Astrophys. J. Lett. 793 (2) (2014) L40.arXiv: 1406.2209,doi:10.1088/2041-8205/793/2/ L40

  61. [62]

    A 6% measurement of the Hubble parameter at $z\sim0.45$: direct evidence of the epoch of cosmic re-acceleration

    M. Moresco, L. Pozzetti, A. Cimatti, R. Jimenez, C. Maraston, L. Verde, D. Thomas, A. Citro, R. Tojeiro, D. Wilkin- son, A 6% measurement of the Hubble parameter atz∼0.45: direct evidence of the epoch of cosmic re-acceleration, JCAP 05 (2016) 014.arXiv:1601.01701, doi:10.1088/1475-7516/2016/05/014

  62. [63]

    A general test of the Copernican Principle

    C. Clarkson, B. Bassett, T. H.-C. Lu, A general test of the Copernican Principle, Phys. Rev. Lett. 101 (2008) 011301.arXiv: 16 0712.3457,doi:10.1103/PhysRevLett.101. 011301

  63. [64]

    Planck 2018 results. V. CMB power spectra and likelihoods

    N. Aghanim, et al., Planck 2018 results. V. CMB power spectra and likelihoods, Astron. Astrophys.641(2020)A5.arXiv:1907.12875, doi:10.1051/0004-6361/201936386

  64. [65]

    Cobaya: Code for Bayesian Analysis of hierarchical physical models

    J. Torrado, A. Lewis, Cobaya: Code for Bayesian Analysis of hierarchical physical models, JCAP 05 (2021) 057.arXiv: 2005.05290,doi:10.1088/1475-7516/2021/ 05/057

  65. [66]

    The Cosmic Linear Anisotropy Solving System (CLASS) I: Overview

    J. Lesgourgues, The Cosmic Linear Anisotropy Solving System (CLASS) I: Overview (2011). arXiv:1104.2932

  66. [67]

    D. Blas, J. Lesgourgues, T. Tram, The Cosmic Linear Anisotropy SolvingSystem (CLASS) II: Approximation schemes (2011).arXiv:1104. 2933

  67. [68]

    Planck 2018 results. VIII. Gravitational lensing

    N. Aghanim, et al., Planck 2018 results. VIII. Gravitational lensing, Astron. Astrophys. 641 (2020) A8.arXiv:1807.06210,doi:10.1051/ 0004-6361/201833886

  68. [69]

    Gelman, D

    A. Gelman, D. B. Rubin, Inference from It- erative Simulation Using Multiple Sequences, Statist. Sci. 7 (1992) 457–472.doi:10.1214/ ss/1177011136

  69. [70]

    Cosmological parameters from CMB and other data: a Monte-Carlo approach

    A. Lewis, S. Bridle, Cosmological parame- ters from CMB and other data: A Monte Carlo approach, Phys. Rev. D 66 (2002) 103511.arXiv:astro-ph/0205436,doi:10. 1103/PhysRevD.66.103511

  70. [71]

    GetDist: a Python package for analysing Monte Carlo samples

    A. Lewis, GetDist: a Python package for analysing Monte Carlo samples, JCAP 08 (2025) 025.arXiv:1910.13970,doi:10. 1088/1475-7516/2025/08/025

  71. [72]

    CMB power spectra and cosmological parameters from Planck PR4 with CamSpec

    E. Rosenberg, S. Gratton, G. Efstathiou, CMB power spectra and cosmological param- eters from Planck PR4 with CamSpec, Mon. Not. Roy. Astron. Soc. 517 (3) (2022) 4620– 4636.arXiv:2205.10869,doi:10.1093/ mnras/stac2744

  72. [73]

    M. S. Madhavacheril, et al., The Atacama Cos- mology Telescope: DR6 Gravitational Lens- ing Map and Cosmological Parameters, As- trophys. J. 962 (2) (2024) 113.arXiv:2304. 05203,doi:10.3847/1538-4357/acff5f

  73. [74]

    W. J. Wolf, C. García-García, P. G. Fer- reira, RobustnessofDarkEnergyPhenomenol- ogy Across Different Parameterizations (2025). arXiv:2502.04929

  74. [75]

    D. H. Lee, W. Yang, E. Di Valentino, S. Pan, C. van de Bruck, Shape of Dark Energy: Constraining Its Evolution with a General Parametrization, Phys. Rev. D (2026).arXiv: 2507.11432,doi:10.1103/z7y2-yvhg

  75. [76]

    An overview of what current data can (and cannot yet) say about evolving dark energy

    W. Giarè, T. Mahassen, E. Di Valentino, S. Pan, An overview of what current data can (and cannot yet) say about evolving dark energy, Phys. Dark Univ. 48 (2025) 101906. arXiv:2502.10264

  76. [77]

    Dynamical Dark Energy Beyond Planck? Constraints from multiple CMB probes, DESI BAO and Type-Ia Supernovae

    W. Giarè, Dynamical Dark Energy Beyond Planck? Constraints from multiple CMB probes, DESI BAO and Type-Ia Supernovae, Phys. Rev. D (2025).arXiv:2409.17074, doi:10.1103/ss37-cxhn

  77. [78]

    A. J. Ross, L. Samushia, C. Howlett, W. J. Percival, A. Burden, M. Manera, The cluster- ing of the SDSS DR7 main Galaxy sample I: A 4 per cent distance measure at z = 0.15, Mon. Not. Roy. Astron. Soc. 449 (1) (2015) 835– 847.arXiv:1409.3242,doi:10.1093/mnras/ stv154

  78. [79]

    Robust Preference for Dynamical Dark Energy in DESI BAO and SN Measurements

    W. Giarè, M. Najafi, S. Pan, E. Di Valentino, J. T. Firouzjaee, Robust Preference for Dy- namical Dark Energy in DESI BAO and SN Measurements, JCAP 10 (2024) 035.arXiv: 2407.16689,doi:10.1088/1475-7516/2024/ 10/035

  79. [80]

    G. Gu, X. Wang, Y. Wang, G.-B. Zhao, L. Pogosian, et al., Dynamical Dark Energy in light of the DESI DR2 Baryonic Acous- tic Oscillations Measurements (2025).arXiv: 2504.06118

  80. [81]

    Soundness of Dark Energy properties

    E. Di Valentino, S. Gariazzo, O. Mena, S. Vagnozzi, Soundness of Dark Energy prop- erties, JCAP 07 (07) (2020) 045.arXiv: 2005.02062,doi:10.1088/1475-7516/2020/ 07/045. 17