Subir Sarkar
University of Oxford
Date
15 November 2023
Host
Thomas Gehrmann
Title
A challenge to the cosmological standard model
Abstract
In the ΛCDM cosmological model the Universe is assumed to be isotropic & homogeneous when averaged on large scales. That the CMB has a dipole anisotropy is interpreted as due to our peculiar (non-Hubble) motion because of local inhomogeneity. There must then be a corresponding dipole in the sky distribution of sources at high redshift. Using catalogues of radio sources & quasars we find that this expectation is rejected at >5σ, i.e. the distribution of distant matter is not isotropic in the ‹CMB frame’. This calls into question the standard practice of boosting to this frame for analysing cosmological data, in particular to infer an isotropic acceleration of the Hubble expansion rate from Type Ia supernovae, which is then interpreted as due to a Cosmological Constant Λ.
Recording & Presentation
