2015/09/30 by Enrico Barausse, Kent Yagi
Physics and Astronomy · #gr-qc #astro-ph.CO #hep-th
paper · pdf · doi:10.1103/physrevlett.115.211105
published as Phys. Rev. Lett. 115, 211105 (2015) · 6 pages. Minor changes to match version accepted for publication in PRL
arxiv created 2015/11/04 · arxiv updated 2015/11/25
Gravity theories beyond General Relativity typically predict dipolar gravitational emission by compact-star binaries. This emission is sourced by "sensitivity" parameters depending on the stellar compactness. We introduce a general formalism to calculate these parameters, and show that in shift-symmetric Horndeski theories stellar sensitivities and dipolar radiation vanish, provided that the binary's dynamics is perturbative (i.e. the post-Newtonian formalism is applicable) and cosmological-expansion effects can be neglected. This allows reproducing the binary-pulsar observed orbital decay.