English

Mapping the redshift drift at various redshifts through cosmography

Cosmology and Nongalactic Astrophysics 2026-04-06 v1 General Relativity and Quantum Cosmology

Abstract

The redshift drift provides a kinematic test of the cosmic expansion history through the slow time variation of the redshift of comoving sources. Motivated by the expected Sandage-Loeb measurements from future facilities, we investigate the drift within a cosmographic framework, modeling the Hubble rate through both a second-order Taylor expansion and a (2,1)(2,1) Pad\'e approximant. We constrain the cosmographic parameters (H0,q0,j0)(H_0,q_0,j_0) by combining Pantheon+ and SH0ES type Ia supernovae with gamma-ray bursts and then examine the impact of adding baryon acoustic oscillation measurements from the second DESI data release. The resulting constraints are used to construct a mock Sandage-Loeb catalog, after which the analyses are repeated including the simulated drift data. In this way, we assess the internal consistency of the reconstructed background rather than perform an independent forecast. Accordingly, we find that, for the SNeIa+GRB analysis, the Taylor reconstruction is compatible at the 1σ1\sigma level with the ω0ω1\omega_0\omega_1CDM scenario, whereas the Pad\'e parameterization improves the agreement of q0q_0 with the Λ\LambdaCDM paradigm. Once DESI BAO data are included, the agreement with the reference background models weakens to the 2σ2\sigma level. The addition of the mock Sandage-Loeb sample mainly tightens the bounds on q0q_0 and j0j_0, with moderate shifts in the central values. We finally compare the reconstructed redshift drift with the corresponding behavior predicted by the Λ\LambdaCDM and ω0ω1\omega_0\omega_1CDM scenarios.

Keywords

Cite

@article{arxiv.2604.03167,
  title  = {Mapping the redshift drift at various redshifts through cosmography},
  author = {Anna Chiara Alfano and Orlando Luongo},
  journal= {arXiv preprint arXiv:2604.03167},
  year   = {2026}
}

Comments

15 pages, 4 figures, 3 tables

R2 v1 2026-07-01T11:53:04.163Z