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  • Open Access

Cosmic variance or galaxy bias? Disentangling finite-volume and galaxy formation effects in cosmological analysis

Francesco Sinigaglia1,2,3,4,* and Francisco-Shu Kitaura5,6

  • *Contact author: fsinigag@sissa.it
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Phys. Rev. D 114, 023564 – Published 28 July, 2026

DOI: https://doi.org/10.1103/1dqk-pq4q

Abstract

Current and forthcoming galaxy redshift surveys, such as DESI and Euclid, are going to bring cosmological analysis to an unprecedentedly exquisite level of precision in the determination of the cosmological parameters. However, these efforts require a high degree of control over theory and systematics, to obtain unbiased results. In this sense, the cosmic variance associated to finite-volume effects represents a major challenge and should adequately accounted for. In this work, we revisit the definition of cosmic variance and develop a novel framework to describe it using a “galaxy biasing” formalism. In particular, we use halo/galaxy Eulerian perturbation theory to relate the density field from an arbitrary cosmic realization to its counterpart having statistical properties reproducing the ensemble average, introducing a new set of bias parameters. We then apply this idea to the description of the nonlinear shift of baryon acoustic oscillations (BAO), disentangling the source of uncertainty from cosmic variance and galaxy biasing associated with the measurement of the BAO scale. We finally check our analytical argument against cosmological variance-suppressed N-body simulations, finding an expected reduction in the uncertainty on the BAO peak position. We conclude that extra care should be used when inferring cosmological information from perturbative approaches involving the estimation of bias parameters and propose new practical strategies to optimally leverage the novel formulation of cosmic variance presented herein in cosmological analysis.

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References (45)

  1. M. Levi, C. Bebek, T. Beers, R. Blum, R. Cahn, D. Eisenstein, B. Flaugher, K. Honscheid, R. Kron, O. Lahav, P. McDonald, N. Roe, D. Schlegel, and representing the DESI Collaboration, The DESI experiment, a whitepaper for snowmass 2013, arXiv:1308.0847.
  2. L. Amendola et al. (The Euclid Theory Working Group), Cosmology and fundamental physics with the Euclid satellite, Living Rev. Relativity 21, 2 (2018).
  3. M. Braglia, X. Chen, and A. Loeb, Exotic dark matter and the DESI anomaly, J. Cosmol. Astropart. Phys. 11 (2025) 064.
  4. U. Kumar, A. Ajith, and A. Verma, Evidence for non-cold dark matter from DESI DR2 measurements, arXiv:2504.14419.
  5. M. Cortês and A. R. Liddle, Interpreting DESI’s evidence for evolving dark energy, J. Cosmol. Astropart. Phys. 12 (2024) 007.
  6. T.-N. Li, P.-J. Wu, G.-H. Du, S.-J. Jin, H.-L. Li, J.-F. Zhang, and X. Zhang, Constraints on interacting dark energy models from the DESI baryon acoustic oscillation and DES supernovae data, Astrophys. J. 976, 1 (2024).
  7. J. Zheng, D.-C. Qiang, and Z.-Q. You, Cosmological constraints on dark energy models using DESI BAO 2024, J. Cosmol. Astropart. Phys. 08 (2025) 056.
  8. L. A. Ureña-López et al., Updated cosmological constraints on axion dark energy with DESI, Phys. Rev. D 112, 103505 (2025).
  9. K. Lodha et al. (DESI Collaboration), DESI 2024: Constraints on physics-focused aspects of dark energy using DESI DR1 BAO data, Phys. Rev. D 111, 023532 (2025).
  10. F. Beutler and E. Di Dio, Modeling relativistic contributions to the halo power spectrum dipole, J. Cosmol. Astropart. Phys. 07 (2020) 048.
  11. C. Bonvin, F. Lepori, S. Schulz, I. Tutusaus, J. Adamek, and P. Fosalba, A case study for measuring the relativistic dipole of a galaxy cross-correlation with the dark energy spectroscopic instrument, Mon. Not. R. Astron. Soc. 525, 4611 (2023).
  12. F. Lepori et al., Euclid: Relativistic effects in the dipole of the two-point correlation function, Astron. Astrophys. 694, A321 (2025).
  13. J. R. Bermejo-Climent et al., Constraints on primordial non-Gaussianity from the cross-correlation of DESI luminous red galaxies and Planck CMB lensing, Astron. Astrophys. 698, A177 (2025).
  14. E. Chaussidon et al., Constraining primordial non-Gaussianity with DESI 2024 LRG and QSO samples, J. Cosmol. Astropart. Phys. 06 (2025) 029.
  15. M. Abdul-Karim et al. (DESI Collaboration), DESI DR2 results II: Measurements of baryon acoustic oscillations and cosmological constraints, Phys. Rev. D 112, 083515 (2025).
  16. M. Abdul-Karim et al. (DESI Collaboration), DESI DR2 results I: Baryon acoustic oscillations from the Lyman alpha forest, Phys. Rev. D 112, 083514 (2025).
  17. F. Bernardeau, S. Colombi, E. Gaztañaga, and R. Scoccimarro, Large-scale structure of the Universe and cosmological perturbation theory, Phys. Rep. 367, 1 (2002).
  18. P. McDonald and A. Roy, Clustering of dark matter tracers: Generalizing bias for the coming era of precision LSS, J. Cosmol. Astropart. Phys. 08 (2009) 020.
  19. K. F. Werner and C. Porciani, Renormalization of linear halo bias in N-body simulations, Mon. Not. R. Astron. Soc. 492, 1614 (2020).
  20. F. S. Kitaura, A. Balaguera-Antolínez, F. Sinigaglia, and M. Pellejero-Ibáñez, The cosmic web connection to the dark matter halo distribution through gravity, Mon. Not. R. Astron. Soc. 512, 2245 (2022).
  21. Y. B. Zel’dovich, Gravitational instability: An approximate theory for large density perturbations, Astron. Astrophys. 5, 84 (1970), https://ui.adsabs.harvard.edu/abs/1970A%26A.....5...84Z/abstract.
  22. B. D. Sherwin and M. Zaldarriaga, Shift of the baryon acoustic oscillation scale: A simple physical picture, Phys. Rev. D 85, 103523 (2012).
  23. C.-H. Chuang, G. Yepes, F.-S. Kitaura, M. Pellejero-Ibanez, S. Rodríguez-Torres, Y. Feng, R. B. Metcalf, R. H. Wechsler, C. Zhao, C.-H. To, S. Alam, A. Banerjee, J. DeRose, C. Giocoli, A. Knebe, and G. Reyes, UNIT project: Universe N-body simulations for the investigation of theoretical models from galaxy surveys, Mon. Not. R. Astron. Soc. 487, 48 (2019).
  24. V. Springel, N. Yoshida, and S. D. M. White, gadget: A code for collisionless and gasdynamical cosmological simulations, New Astron. 6, 79 (2001).
  25. V. Springel, The cosmological simulation code gadget-2, Mon. Not. R. Astron. Soc. 364, 1105 (2005).
  26. Y. Feng, M.-Y. Chu, U. Seljak, and P. McDonald, fastpm: A new scheme for fast simulations of dark matter and haloes, Mon. Not. R. Astron. Soc. 463, 2273 (2016).
  27. X. Xu, N. Padmanabhan, D. J. Eisenstein, K. T. Mehta, and A. J. Cuesta, A 2 per cent distance to z=0.35 by reconstructing baryon acoustic oscillations—II. Fitting techniques, Mon. Not. R. Astron. Soc. 427, 2146 (2012).
  28. M. Vargas-Magaña, S. Ho, X. Xu, A. G. Sánchez, R. O’Connell, D. J. Eisenstein, A. J. Cuesta, W. J. Percival, A. J. Ross, E. Aubourg, J. R. Brownstein, S. Escoffier, D. Kirkby, M. Manera, D. P. Schneider, J. L. Tinker, and B. A. Weaver, The clustering of galaxies in the SDSS-III baryon oscillation spectroscopic survey: Potential systematics in fitting of baryon acoustic feature, Mon. Not. R. Astron. Soc. 445, 2 (2014).
  29. C. Zhao, C.-H. Chuang, F.-S. Kitaura, Y. Liang, M. Pellejero-Ibanez, C. Tao, M. Vargas-Magaña, A. Variu, and G. Yepes, Improving baryon acoustic oscillation measurement with the combination of cosmic voids and galaxies, Mon. Not. R. Astron. Soc. 491, 4554 (2020).
  30. C. Zhao, A. Variu, M. He, D. Forero-Sánchez, A. Tamone, C.-H. Chuang, F.-S. Kitaura, C. Tao, J. Yu, J.-P. Kneib, W. J. Percival, H. Shan, G.-B. Zhao, E. Burtin, K. S. Dawson, G. Rossi, D. P. Schneider, and A. de la Macorra, The completed SDSS-IV extended baryon oscillation spectroscopic survey: Cosmological implications from multitracer BAO analysis with galaxies and voids, Mon. Not. R. Astron. Soc. 511, 5492 (2022).
  31. M. Schmittfull, T. Baldauf, and M. Zaldarriaga, Iterative initial condition reconstruction, Phys. Rev. D 96, 023505 (2017).
  32. R. Hada and D. J. Eisenstein, An iterative reconstruction of cosmological initial density fields, Mon. Not. R. Astron. Soc. 478, 1866 (2018).
  33. F. S. Kitaura, The initial conditions of the universe from constrained simulations, Mon. Not. R. Astron. Soc. 429, L84 (2013).
  34. J. Jasche and B. D. Wandelt, Bayesian physical reconstruction of initial conditions from large-scale structure surveys, Mon. Not. R. Astron. Soc. 432, 894 (2013).
  35. H. Wang, H. J. Mo, X. Yang, and F. C. van den Bosch, Reconstructing the initial density field of the local universe: Methods and tests with mock catalogs, Astrophys. J. 772, 63 (2013).
  36. J. Jasche and G. Lavaux, Physical Bayesian modelling of the non-linear matter distribution: New insights into the nearby universe, Astron. Astrophys. 625, A64 (2019).
  37. F.-S. Kitaura, M. Ata, S. A. Rodríguez-Torres, M. Hernández-Sánchez, A. Balaguera-Antolínez, and G. Yepes, COSMIC BIRTH: Efficient Bayesian inference of the evolving cosmic web from galaxy surveys, Mon. Not. R. Astron. Soc. 502, 3456 (2021).
  38. P. Rosselló, F. S. Kitaura, D. Forero-Sánchez, F. Sinigaglia, and G. Favole, Differentiable fuzzy cosmic-web for field level inference, Astron. Astrophys. 709, A110 (2026).
  39. A. Klypin, F. Prada, and J. Byun, Suppressing cosmic variance with paired-and-fixed cosmological simulations: Average properties and covariances of dark matter clustering statistics, Mon. Not. R. Astron. Soc. 496, 3862 (2020).
  40. F.-S. Kitaura, C.-H. Chuang, Y. Liang, C. Zhao, C. Tao, S. Rodríguez-Torres, D. J. Eisenstein, H. Gil-Marín, J.-P. Kneib, C. McBride, W. J. Percival, A. J. Ross, A. G. Sánchez, J. Tinker, R. Tojeiro, M. Vargas-Magana, and G.-B. Zhao, Signatures of the primordial universe from its emptiness: Measurement of baryon acoustic oscillations from minima of the density field, Phys. Rev. Lett. 116, 171301 (2016).
  41. Y. Liang, C. Zhao, C.-H. Chuang, F.-S. Kitaura, and C. Tao, Measuring baryon acoustic oscillations from the clustering of voids, Mon. Not. R. Astron. Soc. 459, 4020 (2016).
  42. C. Zhao, C. Tao, Y. Liang, F.-S. Kitaura, and C.-H. Chuang, DIVE in the cosmic web: Voids with Delaunay triangulation from discrete matter tracer distributions, Mon. Not. R. Astron. Soc. 459, 2670 (2016).
  43. F. Sinigaglia, F.-S. Kitaura, K. Nagamine, Y. Oku, and A. Balaguera-Antolínez, Field-level Lyman-α forest modeling in redshift space via augmented nonlocal fluctuating Gunn-Peterson approximation, Astron. Astrophys. 682, A21 (2024).
  44. J. M. Coloma-Nadal, F.-S. Kitaura, J. E. García-Farieta, F. Sinigaglia, G. Favole, and D. Forero Sánchez, The hierarchical cosmic web and assembly bias, J. Cosmol. Astropart. Phys. 07 (2024) 083.
  45. F. Sinigaglia, F.-S. Kitaura, K. Nagamine, and Y. Oku, The negative baryon acoustic oscillation shift in the Lyα forest from cosmological simulations, Astrophys. J. Lett. 971, L22 (2024).

Outline

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Phys. Rev. D 114, 023564– Published 28 July, 2026
  • Received 12 January 2026
  • Accepted 9 July 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

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