Article Dans Une Revue Monthly Notices of the Royal Astronomical Society Année : 2026

The Velocity Field Olympics: Assessing velocity field reconstructions with direct distance tracers

Richard Stiskalek
  • Fonction : Auteur
Harry Desmond
  • Fonction : Auteur
Julien Devriendt
  • Fonction : Auteur
Adrianne Slyz
  • Fonction : Auteur
Guilhem Lavaux
Michael J Hudson
  • Fonction : Auteur

Résumé

The peculiar velocity field of the local Universe provides direct insights into its matter distribution and the underlying theory of gravity, and is essential in cosmological analyses for modelling deviations from the Hubble flow. Numerous methods have been developed to reconstruct the density and velocity fields at $z \lesssim 0.05$, typically constrained by redshift-space galaxy positions or by direct distance tracers such as the Tully-Fisher relation, the fundamental plane, or Type Ia supernovae. We introduce a validation framework to evaluate the accuracy of these reconstructions against catalogues of direct distance tracers. Our framework assesses the goodness-of-fit of each reconstruction using Bayesian evidence, residual redshift discrepancies, velocity scaling, and the need for external bulk flows. Applying this framework to a suite of reconstructions -- including those derived from the Bayesian Origin Reconstruction from Galaxies (BORG) algorithm and from linear theory -- we find that the non-linear BORG reconstruction consistently outperforms others. We highlight the utility of such a comparative approach for supernova or gravitational wave cosmological studies, where selecting an optimal peculiar velocity model is essential. Additionally, we present calibrated bulk flow curves predicted by the reconstructions and perform a density-velocity cross-correlation using a linear theory reconstruction to constrain the growth factor, yielding $S_8 = 0.69 \pm 0.034$. This result is in significant tension with Planck but agrees with other peculiar velocity studies.

Dates et versions

hal-04942105 , version 1 (12-02-2025)

Identifiants

Citer

Richard Stiskalek, Harry Desmond, Julien Devriendt, Adrianne Slyz, Guilhem Lavaux, et al.. The Velocity Field Olympics: Assessing velocity field reconstructions with direct distance tracers. Monthly Notices of the Royal Astronomical Society, 2026, 545 (2), pp.staf1960. ⟨10.1093/mnras/staf1960⟩. ⟨hal-04942105⟩
83 Consultations
0 Téléchargements

Altmetric

Partager

  • More