Topic: Cosmological principle

Does the quasar dipole break LambdaCDM?

The Cosmological Principle assumes large-scale homogeneity and isotropy, implying that the cosmic-microwave-background dipole is caused by our motion and that the number-density dipole of distant quasars should agree with it. Recent analyses have reported a larger quasar dipole. This seminar examines selection and estimation systematics and shows how higher multipoles in the quasar density map, plausibly introduced by survey and selection effects, can account for the difference. The result motivates more careful control of systematics before drawing conclusions about the Cosmological Principle or the standard cosmological model.