Optimising the measurement of relativistic distortions in large-scale structure

Understand

It has been shown recently that relativistic distortions generate a dipolar modulation in the two-point correlation function of galaxies.

• To measure this relativistic dipole it is necessary to cross-correlate different populations of galaxies with for example different luminosities or colours.
• In this paper, we construct an optimal estimator to measure the dipole with multiple populations.
• We show that this estimator increases the signal-to-noise of the dipole by up to 35 percent.