All-sky analysis of astrochronometric signals induced by gravitational
  waves
  We introduce a unified formalism to describe both timing and astrometric
perturbations induced on astrophysical point sources by gravitational waves
using a complex spin field on the sphere. This allows the use of spin-weighted
spherical harmonics to analyse "astrochronometric" observables. This approach
simplifies the interpretation and simulation of anisotropies induced in the
observables by gravitational waves. It also allows a simplified derivation of
angular cross-spectra of the observables and their relationship with
generalised Hellings-Downs correlation functions. The spin-weighted formalism
also allows an explicit connection between correlation components and the spin
of gravitational wave polarisations and any presence of chirality. We also
calculate expected signal-to-noise ratios for observables to compare the
utility of timing and deflection observables.
