The multipole expansion of the local expansion rate

Basheer Kalbouneh (1) , Christian Marinoni (1) , Julien Bel (1)

1 CPT - Centre de Physique Théorique - UMR 7332

We design a new observable, the expansion rate fluctuation $\eta$, to characterize deviations from the linear relation between redshift and distance in the local universe. We also show how to compress the resulting signal into spherical harmonic coefficients in order to better decipher the structure and symmetries of the anisotropies in the local expansion rate. We apply this analysis scheme to several public catalogs of redshift-independent distances, the Cosmicflows-3 and Pantheon data sets, covering the redshift range $0.01

Domaines: Astrophysique [astro-ph]

Basheer Kalbouneh, Christian Marinoni, Julien Bel. The multipole expansion of the local expansion rate. Physical Review D, 2023, 107 (2), pp.023507. ⟨10.1103/PhysRevD.107.023507⟩. ⟨hal-03838356⟩