PIRSA:26090048

Video URL

https://pirsa.org/26090048

Does the quasar dipole break LambdaCDM?

Abghari, A. (2026). Does the quasar dipole break LambdaCDM?. Perimeter Institute for Theoretical Physics. https://pirsa.org/26090048

Abghari, Arefe. Does the quasar dipole break LambdaCDM?. Perimeter Institute for Theoretical Physics, Sep. 22, 2026, https://pirsa.org/26090048 

          @misc{ scivideos_PIRSA:26090048,
            doi = {10.48660/26090048},
            url = {https://pirsa.org/26090048},
            author = {Abghari, Arefe},
            keywords = {Cosmology},
            language = {en},
            title = {Does the quasar dipole break LambdaCDM?},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2026},
            month = {sep},
            note = {PIRSA:26090048 see, \url{https://scivideos.org/pirsa/26090048}}
          }

Arefe Abghari UBC

Talk numberPIRSA:26090048
DOI10.48660/26090048
Source RepositoryPIRSA
Collection
Talk Type Scientific Series
Subject

Abstract

The Cosmological Principle, which assumes that the Universe is homogeneous and isotropic on large scales, is one of the foundations of the standard model of cosmology. One of its consequences is that the cosmic microwave background (CMB) dipole is due to our motion, rather than being an intrinsic anisotropy. This
means that the dipole of the number density of distant sources, such as quasars, should match what is inferred from the CMB. However, there have been some recent claims that the quasar dipole is larger than expected. We investigate the potential origins of this discrepancy, paying particular attention to possible systematic effects in the selection of quasars and in the estimation of the dipole. Specifically, we show that the higher multipoles in the quasar density map, presumably due to survey and selection effects, can account for the observed difference between the quasar and CMB dipoles. Our findings suggest that further studies are needed to carefully assess and minimize systematic effects in the analysis of large-scale structure data, which may have important implications for our understanding of the Cosmological Principle and the standard cosmological model.