Speaker
Description
To date, the most precise measurement of the observer's peculiar velocity comes from the dipole in the Cosmic Microwave Background. This velocity also generates a dipole in the source number counts. However its amplitude is unfortunately also sensitive to specific properties of the sources, that are difficult to determine precisely. Current studies give dipoles well aligned with the CMB dipole, but with a significantly larger amplitude. In this work, we develop an alternative method to measure our velocity from source counts, by using off-diagonal correlations between neighboring spherical harmonic coefficients. We show that these correlations contain both a term sensitive to the source properties and another more pristine one directly given by the observer velocity. We explore the potential of a Euclid-like survey to measure this second contribution, independently of the characteristics of the population of sources. We find that the method can reach a high enough sensitivity to decide the fate of the present "dipole tension", with a significance of up to 6 sigma. With conservative priors on the source properties, we can even reach a precision of ~4%, corresponding to a detection significance of 24 sigma.
