Axial Bianchi I meets drifting extragalactic sources

Abstract

We recompute ab initio the drift of comoving sources in axial Bianchi I universes. Our result resolves the long-standing disagreement between the computations by Quercellini et al from 2009 and by Marcori et al from 2018 in favor of the latter. These computations have a potential impact on Gaia data analysis and cosmological parameter estimation.