From harmonic to Newman-Unti coordinates at the second post-Minkowskian order

Abstract

In this paper, we present the complete transformations of a generic metric from (generalized) harmonic to Newman-Unti coordinates up to the second post-Minkowskian order $(G^2)$. This allows us to determine the asymptotic shear, the Bondi mass aspect, and the angular-momentum aspect at both orders.

v2: 14 pages, clarifications added on harmonic coordinates, to appear in PRD