Pith. sign in

REVIEW 3 major objections 4 minor 139 references

By cross-correlating gravitational waves with neutral-hydrogen maps, one year of next-generation data can measure H0 to ~0.5% and σ8 to ~1.6%, with the cross-spectrum alone giving ~2.9% on H0.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

T0 review · deepseek-v4-flash

2026-08-01 00:32 UTC pith:GI257HCV

load-bearing objection An honest, technically solid forecast whose abstract oversells the cross-correlation: the 0.5% H0 comes from HI auto-correlation; cross-only gives 2.9% H0 and 5.3% sigma8. the 3 major comments →

arxiv 2607.26193 v1 pith:GI257HCV submitted 2026-07-28 astro-ph.CO

Cosmology beyond standard sirens: cross-correlation of gravitational waves and neutral hydrogen intensity mapping

classification astro-ph.CO
keywords gravitational wavesneutral hydrogen21-cm intensity mappingangular cross-correlationstandard sirensHubble constantσ8cosmological parameter forecast
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.

Gravitational-wave mergers and neutral-hydrogen emission are assumed to trace the same cosmic web, so the angular cross-correlation between the two maps peaks only when the assumed distance-redshift law places them at the same physical distances. That geometry lets the method use 21-cm redshifts to calibrate the GW luminosity distances, breaking the redshift-distance degeneracy that limits standard sirens. The paper forecasts that with a next-generation GW network and a large 21-cm intensity-mapping survey, one year of data yields ~0.5% precision on H0, ~1.3% on Ωm, and ~1.6% on σ8, and that the GW-HI cross-spectrum on its own reaches ~2.9% on H0 and ~5.3% on σ8. A sympathetic reader would care because this is a calibration-free probe that simultaneously constrains cosmic expansion and the growth of structure, directly testing the H0 and S8 tensions with data from facilities now being built.

Core claim

Within flat ΛCDM and linear tracer bias, the paper treats binary black-hole mergers and 21-cm brightness temperature as biased tracers of the same dark-matter field, and computes their tomographic angular auto- and cross-spectra exactly, beyond the Limber approximation, including density, velocity, lensing, and gravity terms. The central result is a forecast: combining the full auto-plus-cross matrix for the most powerful GW network considered (two Einstein Telescope sites plus one Cosmic Explorer) with a next-generation single-dish 21-cm survey recovers the injected cosmology with H0 to ~0.5%, Ωm to ~1.2-1.3%, and σ8 to ~1.6%, while the isolated GW-HI cross-spectrum alone gives ~2.9% on H0,

What carries the argument

The carrying object is the tomographic angular power spectrum between pairs of biased tracers, C_ℓ^XY(z_i, z_j), with the GW-HI cross-spectrum as the central quantity. The cross-spectrum cancels tracer-specific errors if the two surveys' noises are independent; the HI auto-spectrum supplies high-precision redshift bins that calibrate the GW distance-redshift relation, and the GW auto-spectrum adds the clustering of BBH events. The spectra are computed exactly, avoiding the Limber approximation and retaining relativistic number-count corrections, and the likelihood uses Gaussian covariance with full MCMC sampling.

Load-bearing premise

The forecast assumes both GW sources and neutral hydrogen are linear, biased tracers of the same dark-matter field with the adopted fixed bias functions, and that their measurement errors are uncorrelated; if the actual GW bias differs or foreground residuals correlate with the HI signal, the recovered parameters shift beyond the quoted error bars.

What would settle it

Generate a mock with a GW bias 20% different from the adopted bGW(z), or inject foreground residuals correlated between the two surveys, and rerun the pipeline; if the recovered H0 or σ8 shifts by more than the statistical error bars, the cross-correlation method's claimed systematics cancellation fails.

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

If this is right

  • One year of operation of the most sensitive next-generation GW network plus a large 21-cm survey would give a ~0.5% measurement of H0, independent of the cosmic distance ladder and of CMB calibration.
  • The same data would constrain the late-time clustering amplitude σ8 to ~1.6%, a handle standard-siren methods do not provide and a direct probe of growth-of-structure tensions within ΛCDM.
  • Even if foreground residuals make the 21-cm auto-spectrum unusable, the GW-HI cross-spectrum alone still yields ~2.9% H0, ~9% Ωm, and ~5.3% σ8.
  • The tomographic range z≈0.5-3.5 covers the post-reionization expansion history, enabling checks of H0 and growth beyond single-parameter constraints.

Where Pith is reading between the lines

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

  • The paper's sub-percent headline is almost entirely carried by the HI auto-correlation; if the real 21-cm survey delivers broader redshift bins or noisier foreground cleaning than assumed, the forecast slides toward the cross-only ~3% numbers.
  • Because the bias functions are fixed to literature values rather than marginalized, the quoted σ8 error likely underestimates the true uncertainty; adding bias nuisance parameters would be a natural stress test.
  • A first empirical test could come before the next-generation GW era by cross-correlating existing low-redshift 21-cm maps with current GW catalogs, since the same formalism applies at z≈0.4.
  • The modular pipeline should extend naturally to other tracers, such as optical galaxy surveys, the Lyman-α forest, or fast radio bursts, which would reduce reliance on a single HI survey.

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 / 4 minor

Summary. The paper develops a forecast pipeline for cosmological parameter estimation from the tomographic angular auto- and cross-correlation power spectra of gravitational-wave (GW) events and neutral hydrogen (HI) intensity mapping, focusing on Einstein Telescope (ET) configurations plus SKAO. It uses realistic GW mock catalogs from GWFish+Priors, exact beyond-Limber relativistic spectra computed with a Multi_CLASS fork, and MontePython MCMC sampling of {ωcdm, H0, ln(10^10 As)}. The claimed main results are a ~0.5% H0 constraint, ~1.3% Ωm, and ~1.6% σ8 for the combined 'FullMatrix' analysis, with the GW×HI cross-correlation alone yielding ~2.9% H0 and ~5.3% σ8 in the extended parameter run. The paper reports detector comparisons, a 'broadHi' diagnostic, and a large public code release.

Significance. The pipeline is internally consistent, and the public release of the code and likelihood modules is a valuable contribution. The exact, beyond-Limber treatment of the angular power spectra and the use of full MCMC rather than Fisher forecasts are also strengths. However, the headline 'robust sub-percent H0' result is not a property of the GW×HI cross-correlation method as claimed: the paper's own Appendix C and Fig. 4b show that the FullMatrix posteriors are essentially identical to the HI auto-correlation posteriors and are 'independent of GW data.' The truly new cross-correlation component gives substantially weaker constraints, and the quoted errors are conditional on fixed bias functions and a single self-recovery mock. If the claims are reframed accordingly, the work is a useful forecast for the ET-SKAO synergy; as written, the central robustness claim is overstated.

major comments (3)
  1. [§3.2, Fig. 4b, Appendix C; Abstract] The Abstract attributes the '~0.5%' H0 precision to the 'cross-correlation method' and to its mitigation of tracer-specific systematics. The manuscript itself states in §3.2 that the FullMatrix contours 'completely overlap' with the HI×HI auto posteriors and are 'independent of GW data'; Appendix C confirms 0.7% vs. 0.8% H0 (FullMatrix vs HI auto) in the broad-HI setup. Thus the sub-percent headline is an HI auto-correlation forecast with fixed bHI, not a demonstration of the cross-correlation's robustness. The cross-correlation-only results are 2.9% (H0) and 9% (Ωm) in §3.2, and 15.8% (H0) and 5.3% (σ8) in §3.3 when As is free. The abstract and conclusions should be revised so the 'sub-percent' claim is not attributed to the cross-correlation method.
  2. [§2.3, Eqs. (2.15), (2.24), Table 3] The MCMC varies only ωcdm, H0, and ln(10^10 As); the GW and HI bias functions bGW(z) and bHI(z) are fixed at their fiducial forms. The mock data are generated with the same bias functions, so the quoted 1σ contours are conditional on the tracer model being exactly true. No bias marginalization or systematic-offset injection is performed. Since the HI auto-spectrum scales as bHI^2 P(k), a 10% error in bHI amplitude is roughly a 10% error in the inferred bHI σ8 combination, while a redshift-dependent bias error can mimic geometry and shift H0 and Ωm. The 'robustness' language in §1 and the Abstract therefore requires either bias marginalization or an explicit wrong-bias/offset-recovery test.
  3. [§2.2.2, Eq. (2.29), §3.1] The cross-spectrum in Eq. (2.29) contains no noise term, only beam damping; the foreground residual noise N_fg is included only in the HI auto-spectrum (Eqs. 2.28–2.32). The claimed systematics cancellation assumes that residual foregrounds and other tracer-specific errors are perfectly uncorrelated between surveys. This is an assumption, not a demonstrated property. The manuscript includes no test injecting correlated foreground residuals or shared calibration errors. At minimum, an injection/recovery test with plausible correlated residuals should be added, or the 'robustness' claim should be explicitly limited to purely statistical errors.
minor comments (4)
  1. [Footnote 9 / Eq. (2.34)] The statement CXY(x1,x2) ≠ CXY(x2,x1) appears inconsistent with the symmetry of a cross-spectrum unless a specific non-symmetric convention is intended; please clarify or correct.
  2. [Table 2 and Fig. 9 captions] The detector name is written inconsistently as 'ET2-CE' in Table 2 and elsewhere; it should be ET2L+CE.
  3. [Appendix C, Fig. 9 caption/body] There are repeated 'from' constructions ('degrading to from 3% to 4%... from 9% to 12.5%' and 'from 0.5% to 0.7%'); please edit for clarity.
  4. [Fig. 2] The notation 'Pℓ Σℓ C̃HI,GW' is used without defining the sum or the normalization; please define or replace with the standard Cℓ notation.

Circularity Check

0 steps flagged

No circular derivation: the cosmological-parameter forecast is self-contained, with explicit external bias functions and an independent likelihood; the abstract's cross-correlation framing is overstated but not circular.

full rationale

No circular step reduces a predicted quantity to a fitted input by construction. The theory chain (Eq. 2.8, transfer functions, Eq. 2.11; likelihood Eqs. 2.35-2.37; MCMC sampling of omega_cdm, H0, ln(10^10 As)) is a standard self-contained forecast. The bias functions b_GW(z) (Eq. 2.15) and b_HI(z) (Eq. 2.24) are adopted from external references [107] and [116] as fixed inputs; they are not derived from the parameters being sampled. Eq. (2.29) sets the cross-spectrum additive noise to zero because the two tracer noises are assumed uncorrelated; this is an explicit modeling assumption, not a conclusion obtained from the data. The MCMC recovery of injected fiducial values is a pipeline self-consistency check, not an external validation, and does not make the forecast circular. Appendix C explicitly discloses that the FullMatrix precision is driven by the HI auto-correlation (0.7% vs 0.8% for H0 in the broad-HI diagnostic), and the cross-correlation-only result is 2.9% H0; this is a presentation/robustness caveat, not a circular reduction. The self-referential calibration K_fg from the average C^{Hi,Hi} (Eq. 2.32) is a noise-model choice that affects error bars, but it is a fixed constant and not a fitted cosmological parameter. Same-group citations (e.g., Refs. [54,87,100-102]) are present but are not load-bearing proofs; they motivate binning, provide comparison forecasts, or describe software. The central forecast therefore does not reduce by construction to its own inputs.

Axiom & Free-Parameter Ledger

10 free parameters · 7 axioms · 0 invented entities

The forecast's precision numbers are conditional on a long chain of adopted inputs: external bias fits for both tracers, a fitted ΩHI(z) redshift dependence, a signal-calibrated foreground residual, SKA noise parameters, and an assumed BBH population and detection rate (~10^5 events/yr). None of these carry uncertainties into the quoted error bars, so the 0.5%/1.6% figures are statistical-only precision under the fiducial model. No new entities are introduced.

free parameters (10)
  • bHI(z) selection bias coefficients = aHI=0.22, bHI=1.47, cHI=0.63
    Eq. (2.24): HI bias fitted to the semi-analytic model of Ref. [116]; sets the HI clustering amplitude and hence the σ8 and H0 constraints. Uncertainty not propagated.
  • bGW(z) selection bias coefficients = aGW=0.948, bGW=-0.553, cGW=0.996, dGW=1.034
    Eq. (2.15) from Ref. [107]; GW bias enters the cross-spectrum amplitude; weakly measured observationally, and no marginalization is performed.
  • ΩHI(z) = 4(1+z)^0.6 × 10^-4 normalization = 4×10^-4 at z=0 with exponent 0.6
    Eq. (2.22) from Ref. [115] column-density fits; sets Tb(z) (Eq. 2.23), which calibrates the HI signal amplitude and the evolution bias.
  • Foreground residual normalization Kfg = ≈6×10^-7
    Eq. (2.32): 'normalization constant derived from the average value of C^{Hi,Hi}' — calibrated to the signal it contaminates; the HI noise floor and hence the sub-percent H0 precision inherit this self-calibration.
  • Foreground shape parameters Afg, bfg, cfg = Afg≈0.129, bfg≈-0.081, cfg≈0.581
    Eq. (2.32) from Ref. [119] foreground-removal simulations; adopted as fixed.
  • SKA instrumental noise parameters = Tsys=28 K, B=20 MHz, tobs=1.8×10^7 s, Sarea=20000 deg², Ndish=254
    Eq. (2.31): single-dish noise model drives the HI auto-correlation S/N, which dominates the quoted constraints.
  • GW redshift-distribution fit parameters αGW, βGW, γGW = per network, Table 1 (ET2L+CE: 3.243×10^5, 3.0532, 2.1555)
    Eq. (2.14) fitted to GWFish+Priors mock catalogs; sets the ~10^5/yr detection rate, the dominant driver of GW-side statistical weight.
  • BBH population + rate model = PowerLaw+Peak masses; Madau–Dickinson SFR; ρ≥8 threshold
    Section 2.2.1: merger rate and mass distribution from GWTC-3-consistent population (Refs. [35,102]); the detection rate scales all GW constraints.
  • Magnification bias sHI = 0.4
    Eq. (2.25): constant adopted from Ref. [113]; enters relativistic number counts, subdominant.
  • Effective GW beam damping ℓdamp per bin = 12–20 (ET-Δ), 69–229 (ET2L+CE), Table 2
    Eq. (2.19) computed from mock-catalog sky localization; sets which multipoles survive, and hence whether a network constrains anything at all.
axioms (7)
  • standard math Standard flat ΛCDM with linear perturbation theory; no mode coupling between multipoles
    Section 2.3: the Cℓ covariance (Eq. 2.37) assumes Gaussian, diagonal ℓ-blocks.
  • domain assumption GW sources and HI emission are linearly biased tracers of the same dark-matter density field
    Sections 1–2.2: the entire cross-correlation method rests on shared clustering; if the two tracers do not trace the same field, the method measures nothing.
  • domain assumption Tracer-specific errors (GW noise, HI foreground residuals, instrumental noise) are statistically independent and cancel in the cross-spectrum
    Eq. (2.29) contains no noise term for GW×HI; this is the load-bearing 'robustness' premise, never tested by injecting correlated systematics.
  • standard math Gaussian likelihood for Cℓ with covariance from the simulated spectra
    Section 2.3 (Eqs. 2.35–2.37): standard but inaccurate at low ℓ / low mode counts (relevant for ET-Δ with ℓdamp~12–20, where only a handful of modes exist).
  • standard math Exact beyond-Limber relativistic integration (Multi_CLASS fork) is correct
    Section 2.1 and Refs. [97–99]: central technical improvement; correctness rests on external, non-machine-checked code.
  • domain assumption BBH merger rate follows Madau–Dickinson star formation and PowerLaw+Peak mass distribution
    Section 2.2.1 via icarogw [102]; detection counts (~10^5/yr) and thus all GW-informed contours scale with this choice.
  • domain assumption SKAO single-dish sensitivity numbers (Tsys, bandwidth, survey area) are realistic
    Section 2.2.2 from SKA Red Book [81]; the HI auto-correlation dominates the final constraints, so these numbers set the headline precision.

pith-pipeline@v1.3.0-alltime-deepseek · 27103 in / 25567 out tokens · 232973 ms · 2026-08-01T00:32:39.971868+00:00 · methodology

0 comments
read the original abstract

We explore the potential of cross-correlation between gravitational wave (GW) events and neutral hydrogen (HI) intensity mapping surveys to serve as an independent cosmological probe. Focusing on the ET and the SKAO, and assuming that binary black hole mergers and HI emission are biased tracers of the underlying dark matter distribution, we use their angular auto- and cross-correlation spectra to constrain cosmological parameters. We test three different GW detector networks: ET alone, both in its $\Delta$ and 2L configuration, and ET-2L together with Cosmic Explorer. We show that the cross-correlation method, by naturally mitigating tracer-specific systematics, yields robust cosmological bounds, allowing for a sub-percent ($\sim 0.5\%$) precision on the Hubble constant $H_\mathrm{0}$. Furthermore, this approach robustly constrains the cosmic expansion history throughout the post-reionization era of the Universe and, unlike conventional standard sirens, simultaneously probes the large scale distribution of matter perturbations, achieving relative uncertainties of approximately 1.3% on the total matter density $\Omega_\mathrm{m}$ and 1.6% on the late-time clustering amplitude $\sigma_8$.

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

139 extracted references · 11 linked inside Pith

  1. [1]

    A. G. Riess et al. Observational evidence from supernovae for an accelerating universe and a cosmological constant.Astron. J., 116:1009–1038, 1998. – 22 –

  2. [2]

    Perlmutter et al

    S. Perlmutter et al. Measurements ofΩandΛfrom 42 high redshift supernovae.Astrophys. J., 517:565–586, 1999

  3. [3]

    Aghanim et al

    N. Aghanim et al. Planck 2018 results. VI. Cosmological parameters.Astron. Astrophys., 641:A6, 2020

  4. [4]

    A. G. Riess, S. Casertano, W. Yuan, L. M. Macri, and D. Scolnic. Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination of the Hubble Constant and Stronger Evidence for Physics beyondΛCDM.The Astrophysical Journal, 876(1):85, 2019

  5. [5]

    Font-Ribera et al

    A. Font-Ribera et al. Quasar-lymanαforest cross-correlation from boss dr11: Baryon acoustic oscillations.Journal of Cosmology and Astroparticle Physics, 2014(05):027–027, May 2014

  6. [6]

    Verde, T

    L. Verde, T. Treu, and A. G. Riess. Tensions between the early and late universe.Nature Astronomy, 3(10):891–895, September 2019

  7. [7]

    Mota, Adam G

    Eleonora Di Valentino, Olga Mena, Supriya Pan, Luca Visinelli, Weiqiang Yang, Alessandro Melchiorri, David F. Mota, Adam G. Riess, and Joseph Silk. In the realm of the Hubble tension—a review of solutions.Class. Quant. Grav., 38(15):153001, 2021

  8. [8]

    Marc Kamionkowski and Adam G. Riess. The Hubble Tension and Early Dark Energy, 2023

  9. [9]

    Hubble tension: The evidence of new physics.Universe, 9(2), 2023

    Jian-Ping Hu and Fa-Yin Wang. Hubble tension: The evidence of new physics.Universe, 9(2), 2023

  10. [10]

    Smith, Tanvi Karwal, and Marc Kamionkowski

    Vivian Poulin, Tristan L. Smith, Tanvi Karwal, and Marc Kamionkowski. Early Dark Energy Can Resolve The Hubble Tension.Phys. Rev. Lett., 122(22):221301, 2019

  11. [11]

    Moresco et al

    M. Moresco et al. Unveiling the Universe with emerging cosmological probes.Living Rev. Rel., 25(1):6, 2022

  12. [12]

    Abbott, LIGO Scientific, Virgo Collaboration, KAGRA Collaboration, et al

    B. Abbott, LIGO Scientific, Virgo Collaboration, KAGRA Collaboration, et al. GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral.Phys. Rev. Lett., 119:161101, Oct 2017

  13. [13]

    K. C. Wong et al. H0LiCOW – XIII. A 2.4 per cent measurement of H0 from lensed quasars: 5.3σtension between early- and late-Universe probes.Mon. Not. Roy. Astron. Soc., 498(1):1420–1439, 2020

  14. [14]

    Freedman et al

    Wendy L. Freedman et al. The Carnegie-Chicago Hubble Program. VIII. An Independent Determination of the Hubble Constant Based on the Tip of the Red Giant Branch.The Astrophysical Journal, 7 2019

  15. [15]

    B. F. Schutz. Determining the Hubble constant from gravitational wave observations.Nature, 323(6086):310–311, September 1986

  16. [16]

    Jose María Ezquiaga and Daniel E. Holz. Spectral Sirens: Cosmology from the Full Mass Distribution of Compact Binaries.Phys. Rev. Lett., 129(6):061102, 2022

  17. [17]

    H.-Y. Chen, J. M. Ezquiaga, and I. Gupta. Cosmography with next-generation gravitational wave detectors.Class. Quant. Grav., 41(12):125004, 2024

  18. [18]

    On the possibility of determining cosmological parameters from measurements of gravitational waves emitted by coalescing, compact binaries.Phys

    Dragoljub Markovic. On the possibility of determining cosmological parameters from measurements of gravitational waves emitted by coalescing, compact binaries.Phys. Rev. D, 48:4738–4756, 1993

  19. [19]

    Holz, Scott A

    Neal Dalal, Daniel E. Holz, Scott A. Hughes, and Bhuvnesh Jain. Short grb and binary black hole standard sirens as a probe of dark energy.Phys. Rev. D, 74:063006, Sep 2006

  20. [20]

    B. P. Abbott et al. A gravitational-wave standard siren measurement of the Hubble constant. Nature, 551(7678):85–88, 2017

  21. [21]

    Feeney, Hiranya V

    Stephen M. Feeney, Hiranya V. Peiris, Andrew R. Williamson, Samaya M. Nissanke, Daniel J. Mortlock, Justin Alsing, and Dan Scolnic. Prospects for resolving the Hubble constant tension with standard sirens.Phys. Rev. Lett., 122(6):061105, 2019. – 23 –

  22. [22]

    Palmese, et al., and DES Collaboration

    A. Palmese, et al., and DES Collaboration. A Statistical Standard Siren Measurement of the Hubble Constant from the LIGO/Virgo Gravitational Wave Compact Object Merger GW190814 and Dark Energy Survey Galaxies.ApJL, 900(2):L33, September 2020

  23. [23]

    Accurate standard siren cosmology with joint gravitational-wave andγ-ray burst observations.Phys

    Michele Mancarella, Francesco Iacovelli, Stefano Foffa, Niccolò Muttoni, and Michele Maggiore. Accurate standard siren cosmology with joint gravitational-wave andγ-ray burst observations.Phys. Rev. Lett., 133:261001, Dec 2024

  24. [24]

    Model-independent cosmology with joint observations of gravitational waves andγ-ray bursts.JCAP, 2025(5):021, May 2025

    Andrea Cozzumbo, Ulyana Dupletsa, Rodrigo Calderón, Riccardo Murgia, Gor Oganesyan, and Marica Branchesi. Model-independent cosmology with joint observations of gravitational waves andγ-ray bursts.JCAP, 2025(5):021, May 2025

  25. [25]

    Holz and Scott A

    Daniel E. Holz and Scott A. Hughes. Using gravitational-wave standard sirens.Astrophys. J., 629:15–22, 2005

  26. [26]

    MacLeod and Craig J

    Chelsea L. MacLeod and Craig J. Hogan. Precision of Hubble constant derived using black hole binary absolute distances and statistical redshift information.Phys. Rev. D, 77:043512, 2008

  27. [27]

    Inference of the cosmological parameters from gravitational waves: application to second generation interferometers.Phys

    Walter Del Pozzo. Inference of the cosmological parameters from gravitational waves: application to second generation interferometers.Phys. Rev. D, 86:043011, 2012

  28. [28]

    Measurement of Hubble constant with stellar-mass binary black holes

    Atsushi Nishizawa. Measurement of Hubble constant with stellar-mass binary black holes. Phys. Rev. D, 96(10):101303, 2017

  29. [29]

    Hsin-Yu Chen, Maya Fishbach, and Daniel E. Holz. A two per cent Hubble constant measurement from standard sirens within five years.Nature, 562(7728):545–547, 2018

  30. [30]

    Fishbach et al

    M. Fishbach et al. A Standard Siren Measurement of the Hubble Constant from GW170817 without the Electromagnetic Counterpart.Astrophys. J. Lett., 871(1):L13, 2019

  31. [31]

    Soares-Santos et al

    M. Soares-Santos et al. First Measurement of the Hubble Constant from a Dark Standard Siren using the Dark Energy Survey Galaxies and the LIGO/Virgo Binary–Black-hole Merger GW170814.Astrophys. J. Lett., 876(1):L7, 2019

  32. [32]

    Cosmological inference using gravitational wave standard sirens: A mock data analysis.Phys

    Rachel Gray et al. Cosmological inference using gravitational wave standard sirens: A mock data analysis.Phys. Rev. D, 101(12):122001, 2020

  33. [33]

    B. P. Abbott et al. A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo.Astrophys. J., 909(2):218, 2021

  34. [34]

    Cosmology with LIGO/Virgo dark sirens: Hubble parameter and modified gravitational wave propagation.JCAP, 08:026, 2021

    Andreas Finke, Stefano Foffa, Francesco Iacovelli, Michele Maggiore, and Michele Mancarella. Cosmology with LIGO/Virgo dark sirens: Hubble parameter and modified gravitational wave propagation.JCAP, 08:026, 2021

  35. [35]

    Abbott et al

    R. Abbott et al. Constraints on the cosmic expansion history from gwtc–3.The Astrophysical Journal, 949(2):76, jun 2023

  36. [36]

    Cosmology and modified gravitational wave propagation from binary black hole population models.Phys

    Michele Mancarella, Edwin Genoud-Prachex, and Michele Maggiore. Cosmology and modified gravitational wave propagation from binary black hole population models.Phys. Rev. D, 105:064030, Mar 2022

  37. [37]

    Gair et al

    Jonathan R. Gair et al. The Hitchhiker’s Guide to the Galaxy Catalog Approach for Dark Siren Gravitational-wave Cosmology.Astron. J., 166(1):22, 2023

  38. [38]

    Joint cosmological and gravitational-wave population inference using dark sirens and galaxy catalogues.JCAP, 12:023, 2023

    Rachel Gray et al. Joint cosmological and gravitational-wave population inference using dark sirens and galaxy catalogues.JCAP, 12:023, 2023

  39. [39]

    Cosmology and Astrophysics with Standard Sirens and Galaxy Catalogs in View of Future Gravitational Wave Observations.Astrophys

    Nicola Borghi, Michele Mancarella, Michele Moresco, Matteo Tagliazucchi, Francesco Iacovelli, Andrea Cimatti, and Michele Maggiore. Cosmology and Astrophysics with Standard Sirens and Galaxy Catalogs in View of Future Gravitational Wave Observations.Astrophys. J., 964(2):191, 2024. – 24 –

  40. [40]

    Clecio R. Bom, V. Alfradique, A. Palmese, G. Teixeira, L. Santana-Silva, A. Santos, and P. Darc. A dark standard siren measurement of the Hubble constant following LIGO/Virgo/KAGRA O4a and previous runs.Mon. Not. Roy. Astron. Soc., 535(1):961–975, 2024

  41. [41]

    Standard Sirens in 2040s: Probing the Cosmic Expansion History with Gravitational Waves and Spectroscopic Galaxy Surveys.ArXiv e-prints, dec 2025

    Nicola Borghi et al. Standard Sirens in 2040s: Probing the Cosmic Expansion History with Gravitational Waves and Spectroscopic Galaxy Surveys.ArXiv e-prints, dec 2025. arXiv:2512.18369

  42. [42]

    GWTC-5.0: Constraints on the cosmic expansion rate and modified gravitational-wave propagation, 2026

    The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration. GWTC-5.0: Constraints on the cosmic expansion rate and modified gravitational-wave propagation, 2026. arXiv:2605.27227

  43. [43]

    Chernoff and Lee Samuel Finn

    David F. Chernoff and Lee Samuel Finn. Gravitational radiation, inspiraling binaries, and cosmology.Astrophys. J. Lett., 411:L5–L8, 1993

  44. [44]

    Taylor and Jonathan R

    Stephen R. Taylor and Jonathan R. Gair. Cosmology with the lights off: standard sirens in the Einstein Telescope era.Phys. Rev. D, 86:023502, 2012

  45. [45]

    Standard-siren cosmology using gravitational waves from binary black holes.Astrophys

    Zhi-Qiang You, Xing-Jiang Zhu, Gregory Ashton, Eric Thrane, and Zong-Hong Zhu. Standard-siren cosmology using gravitational waves from binary black holes.Astrophys. J., 908(2):215, 2021

  46. [46]

    Cosmology with standard sirens at cosmic noon.Phys

    Christine Ye and Maya Fishbach. Cosmology with standard sirens at cosmic noon.Phys. Rev. D, 104(4):043507, 2021

  47. [47]

    Steer, Stephane Perries, and Gregoire Pierra

    Simone Mastrogiovanni, Danny Laghi, Rachel Gray, Giada Caneva Santoro, Archisman Ghosh, Christos Karathanasis, Konstantin Leyde, Daniele A. Steer, Stephane Perries, and Gregoire Pierra. Joint population and cosmological properties inference with gravitational waves standard sirens and galaxy surveys.Phys. Rev. D, 108(4):042002, 2023

  48. [48]

    Ferraiuolo, S

    S. Ferraiuolo, S. Mastrogiovanni, S. Escoffier, and E. Kajfasz. Inferring astrophysics and cosmology with individual compact binary coalescences and their gravitational-wave stochastic background.Astron. Astrophys., 701:A36, 2025

  49. [49]

    Spectral siren cosmology from gravitational-wave observations in GWTC-4.0.ArXiv e-prints, 9 2025

    Ignacio Magaña Hernandez and Antonella Palmese. Spectral siren cosmology from gravitational-wave observations in GWTC-4.0.ArXiv e-prints, 9 2025. arXiv:2509.03607

  50. [50]

    Heavy Black-Holes Also Matter in Standard Siren Cosmology.ArXiv e-prints, 2026

    Grégoire Pierra and Alexander Papadopoulos. Heavy Black-Holes Also Matter in Standard Siren Cosmology.ArXiv e-prints, 2026. arXiv:2601.03257

  51. [51]

    Pushing spectral siren cosmology into the third-generation era: a blinded mock data challenge.ArXiv e-prints, 2 2026

    Matteo Tagliazucchi, Michele Moresco, Alessandro Agapito, Michele Mancarella, Sarah Ferraiuolo, Simone Mastrogiovanni, Nicola Borghi, Francesco Pannarale, and Daniele Bonacorsi. Pushing spectral siren cosmology into the third-generation era: a blinded mock data challenge.ArXiv e-prints, 2 2026

  52. [52]

    Spectral sirens cosmology from binary black holes populations with sharper mass features.ArXiv e-prints, 2026

    Tom Bertheas, Vasco Gennari, Danièle Steer, and Nicola Tamanini. Spectral sirens cosmology from binary black holes populations with sharper mass features.ArXiv e-prints, 2026. arXiv:2603.06792

  53. [53]

    C. C. Diaz and S. Mukherjee. Mapping the cosmic expansion history from LIGO-Virgo-KAGRA in synergy with DESI and SPHEREx.Mon. Not. Roy. Astron. Soc., 511(2):2782–2795, 2022

  54. [54]

    Scelfo, M

    G. Scelfo, M. Spinelli, A. Raccanelli, L. Boco, A. Lapi, and M. Viel. Gravitational waves×HI intensity mapping: cosmological and astrophysical applications.JCAP, 01(01):004, 2022

  55. [55]

    Wandelt, and Joseph Silk

    Suvodip Mukherjee, Alex Krolewski, Benjamin D. Wandelt, and Joseph Silk. Cross-correlating dark sirens and galaxies: Constraints on h0 from gwtc-3 of ligo–virgo–kagra.The Astrophysical Journal, 975(2):189, nov 2024

  56. [56]

    Striking a Chord with Spectral Sirens: Multiple Features in the Compact Binary Population Correlate with H0.Astrophys

    Utkarsh Mali and Reed Essick. Striking a Chord with Spectral Sirens: Multiple Features in the Compact Binary Population Correlate with H0.Astrophys. J., 980(1):85, 2025. – 25 –

  57. [57]

    Tashiro, L

    João Ferri, Ian L. Tashiro, L. Raul Abramo, Isabela Matos, Miguel Quartin, and Riccardo Sturani. A robust cosmic standard ruler from the cross-correlations of galaxies and dark sirens.JCAP, 04:008, 2025

  58. [58]

    Pedrotti, M

    A. Pedrotti, M. Mancarella, J. Bel, and D. Gerosa. Cosmology with the angular cross-correlation of gravitational-wave and galaxy catalogs: forecasts for next-generation interferometers and the Euclid survey, 2025. arXiv:2504.10482

  59. [59]

    G. Sala, A. Cuoco, J. Lesgourgues, K.-R. Revis, L. Valbusa Dall’Armi, and S. Casas. Inferring cosmological parameters from galaxy and dark sirens cross-correlation.JCAP, 2026(05):095, may 2026

  60. [60]

    First measurement of the Hubble constant from gravitational wave-galaxy cross-correlations, December 2025

    Isabela Santiago de Matos, Charles Dalang, Tessa Baker, Raul Abramo, João Ferri, and Miguel Quartin. First measurement of the Hubble constant from gravitational wave-galaxy cross-correlations, December 2025. arXiv:2512.15380

  61. [61]

    Large scale structure prior knowledge in the dark siren method.JCAP, 01:034, 2026

    Charles Dalang, Bartolomeo Fiorini, and Tessa Baker. Large scale structure prior knowledge in the dark siren method.JCAP, 01:034, 2026

  62. [62]

    Jiaming Pan, Dragan Huterer, Camille Avestruz, Damon H. T. Cheung, Emery Trott, Neal Dalal, and Donghui Jeong. Determining the Hubble constant through cross-correlation of galaxies and gravitational waves.Phys. Rev. D, 113(10):103532, 2026

  63. [63]

    Cross-Parkin, Cullan Howlett, Leonardo Giani, Chris Blake, and Tamara M

    Madeline L. Cross-Parkin, Cullan Howlett, Leonardo Giani, Chris Blake, and Tamara M. Davis. Dark siren cross-correlations and the sensitivity ofH0 to methodological choices.arXiv e-prints, page arXiv:2605.06783, May 2026. arXiv:2605.06783

  64. [64]

    M. Oguri. Measuring the distance-redshift relation with the cross-correlation of gravitational wave standard sirens and galaxies.Physical Review D, 93(8), April 2016

  65. [65]

    Incompleteness Matters Not: Inference of H0 from Binary Black Hole-Galaxy Cross-correlations.ApJ, 902(1):79, October 2020

    Sayantani Bera, Divya Rana, Surhud More, and Sukanta Bose. Incompleteness Matters Not: Inference of H0 from Binary Black Hole-Galaxy Cross-correlations.ApJ, 902(1):79, October 2020

  66. [66]

    Muherjee and B.D

    S. Muherjee and B.D. Wandelt. Beyond the classical distance-redshift test: cross-correlating redshift-free standard candles and sirens with redshift surveys, 2018. arXiv:1808.06615

  67. [67]

    E. D. Kovetz et al. Line-intensity mapping: 2017 status report, 2017. arXiv:1709.09066

  68. [68]

    José Luis Bernal and Ely D. Kovetz. Line-intensity mapping: theory review with a focus on star-formation lines.The Astronomy and Astrophysics Review, 30(1), September 2022

  69. [69]

    Kovetz et al

    Ely D. Kovetz et al. Astrophysics and Cosmology with Line-Intensity Mapping.Bull. Am. Astron. Soc., 51(3):101, 2020

  70. [70]

    M. G. Santos, P. Bull, D. Alonso, S. Camera, P. G. Ferreira, G. Bernardi, R. M., M. Viel, F. Villaescusa-Navarro, F. B. Abdalla, M. Jarvis, R. B. Metcalf, A. Pourtsidou, and L. Wolz. Cosmology with a SKA HI intensity mapping survey, 2015. arXiv:1501.03989

  71. [71]

    Breysse, and Ely D

    José Luis Bernal, Patrick C. Breysse, and Ely D. Kovetz. Cosmic expansion history from line-intensity mapping.Physical Review Letters, 123(25), December 2019

  72. [72]

    Chang, U.-L

    T.-C. Chang, U.-L. Pen, K. Bandura, and J. B. Peterson. Conservative Constraints on Early Cosmology: an illustration of the Monte Python cosmological parameter inference code. Nature, 466:001, 2010

  73. [73]

    K. W. Masui, E. R. Switzer, N. Banavar, K. Bandura, C. Blake, L.-M. Calin, T.-C. Chang, X. Chen, Y.-C. Li, Y.-W. Liao, A. Natarajan, U.-L. Pen, J. B. Peterson, J. R. Shaw, and T. C. Voytek. Measurement of 21cm brightness fluctuations at z∼0.8 in cross-correlation. The Astrophysical Journal Letters, 763(1):L20, jan 2013

  74. [74]

    C. J. Anderson, N. J. Luciw, Y.-C. Li, C. Y. Kuo, J. Yadav, K. W. Masui, T.-C. Chang, X. Chen, N. Oppermann, Y.-W. Liao, U.-L. Pen, D. C. Price, L. Staveley-Smith, E. R. – 26 – Switzer, P. T. Timbie, and L. Wolz. Low-amplitude clustering in low-redshift 21-cm intensity maps cross-correlated with 2df galaxy densities.Monthly Notices of the Royal Astronomic...

  75. [75]

    Wolz et al

    L. Wolz et al. Hiconstraints from the cross-correlation of eboss galaxies and green bank telescope intensity maps.Monthly Notices of the Royal Astronomical Society, 510(3):3495–3511, December 2021

  76. [76]

    Hill, Gary Hinshaw, Carolin Höfer, T

    CHIME Collaboration, Mandana Amiri, Kevin Bandura, Arnab Chakraborty, Matt Dobbs, Mateus Fandino, Simon Foreman, Hyoyin Gan, Mark Halpern, Alex S. Hill, Gary Hinshaw, Carolin Höfer, T. L. Landecker, Zack Li, Joshua MacEachern, Kiyoshi Masui, Juan Mena-Parra, Nikola Milutinovic, Arash Mirhosseini, Laura Newburgh, Anna Ordog, Sourabh Paul, Ue-Li Pen, Trista...

  77. [77]

    J. Wang, M. G Santos, P. Bull, K. Grainge, S. Cunnington, J. Fonseca, M. O. Irfan, Y. Li, A. Pourtsidou, P. S. Soares, M. Spinelli, G. Bernardi, and B. Engelbrecht. Hiintensity mapping with MeerKAT: calibration pipeline for multidish autocorrelation observations. Monthly Notices of the Royal Astronomical Society, 505(3):3698–3721, May 2021

  78. [78]

    Bernal, Philip Bull, Stefano Camera, Isabella P

    MeerKLASS Collaboration, Matilde Barberi-Squarotti, José L. Bernal, Philip Bull, Stefano Camera, Isabella P. Carucci, Zhaoting Chen, Steven Cunnington, Brandon N. Engelbrecht, José Fonseca, Keith Grainge, Melis O. Irfan, Yichao Li, Aishrila Mazumder, Sourabh Paul, Alkistis Pourtsidou, Mario G. Santos, Marta Spinelli, Jingying Wang, Amadeus Witzemann, and ...

  79. [79]

    M. G. Santos et al. MeerKLASS: MeerKAT large area synoptic survey, 2017. arXiv:1709.06099

  80. [80]

    Braun, T

    R. Braun, T. Bourke, J. A. Green, E. Keane, and J. Wagg. Advancing Astrophysics with the Square Kilometre Array. InAdvancing Astrophysics with the Square Kilometre Array (AASKA14), page 174, April 2015

Showing first 80 references.