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Journal Articles The Astrophysical journal letters Year : 2022

A Challenge to the Standard Cosmological Model

Nathan Secrest
Sebastian von Hausegger
Mohamed Rameez
Roya Mohayaee
Subir Sarkar


Abstract We present the first joint analysis of catalogs of radio galaxies and quasars to determine whether their sky distribution is consistent with the standard ΛCDM model of cosmology. This model is based on the cosmological principle, which asserts that the universe is statistically isotropic and homogeneous on large scales, so the observed dipole anisotropy in the cosmic microwave background (CMB) must be attributed to our local peculiar motion. We test the null hypothesis that there is a dipole anisotropy in the sky distribution of radio galaxies and quasars consistent with the motion inferred from the CMB, as is expected for cosmologically distant sources. Our two samples, constructed respectively from the NRAO VLA Sky Survey and the Wide-field Infrared Survey Explorer, are systematically independent and have no shared objects. Using a completely general statistic that accounts for correlation between the found dipole amplitude and its directional offset from the CMB dipole, the null hypothesis is independently rejected by the radio galaxy and quasar samples with p -values of 8.9 × 10 −3 and 1.2 × 10 −5 , respectively, corresponding to 2.6 σ and 4.4 σ significance. The joint significance, using sample-size-weighted Z -scores, is 5.1 σ . We show that the radio galaxy and quasar dipoles are consistent with each other and find no evidence for any frequency dependence of the amplitude. The consistency of the two dipoles improves if we boost to the CMB frame assuming its dipole to be fully kinematic, suggesting that cosmologically distant radio galaxies and quasars may have an intrinsic anisotropy in this frame.
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Dates and versions

hal-03974420 , version 1 (06-02-2023)





Nathan Secrest, Sebastian von Hausegger, Mohamed Rameez, Roya Mohayaee, Subir Sarkar. A Challenge to the Standard Cosmological Model. The Astrophysical journal letters, 2022, 937 (2), pp.L31. ⟨10.3847/2041-8213/ac88c0⟩. ⟨hal-03974420⟩
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