Extension of Dipole Modulation Formalism to Large-Scale Structure: A Theoretical Framework for Galaxy Number Counts

Abstract The motion of the observer relative to the cosmic rest frame induces a dipolar modulation of number counts and a characteristic ℓ–ℓ + 1 correlation in harmonic space. Building upon recent frameworks that utilize aberration-induced high-ℓ coupling, we advance a relativistic Quadratic Estimator by analytically incorporating the irreducible Poisson shot-noise trispectrum to correct non-Gaussian covariance underestimations. Using analytic forecasts and mock catalogues with survey characteri