Gravitational Radiation at Infinity with Non-Negative Cosmological Constant

The existence of gravitational radiation arriving at null infinity J+, i.e., escaping from the physical system, is addressed in presence a non-negative cosmological constant Λ≥0. case with vanishing Λ well understood and relies on properties News tensor field (or function) defined J+. situation drastically different when Λ>0, where there no known notion ‘News’ similar good properties. In this paper, both situations are considered jointly tidal point view, that is, taking into account strength energy) curvature tensors. fundamental object used for purposes asymptotic (radiant) super-momentum, causal vector remarkable This leads to novel characterization valid general Λ≥0, which has been proven be equivalent Λ=0 standard one based News. Here, implications result Λ>0 analyzed detail. A procedure construct ‘News tensors’ depicted, proposal symmetries provided, an example conserved charge may detect J+ exhibited. series illustrative examples listed as well.