Dynamical scalarization of neutron stars in scalartensor gravity theories
Abstract
We present a framework to study generic neutronstar binaries in scalartensor theories of gravity. Our formalism achieves this goal by suitably interfacing a postNewtonian orbital evolution (described by a set of ordinary differential equations) with a set of nonlinear algebraic equations, which provide a description of the scalar charge of each binary's component along the evolution in terms of isolatedstar data. We validate this semianalytical procedure by comparing its results to those of fully generalrelativistic simulations, and use it to investigate the behavior of binary systems in large portions of the parameter space of scalartensor theories. This allows us to shed further light on the phenomena of "dynamical scalarization," which we uncovered in [E. Barausse et al., Phys. Rev. D 87, 081506(R) (2013)] and which takes place in tight binaries, even for stars that have exactly zero scalar charge in isolation. We also employ our formalism to study representative binary systems, obtain their gravitationalwave signals and discuss the extent to which deviations from general relativity can be detected. The insights gained by this framework allow us to additionally show that eccentric binaries can undergo scalarization/descalarization phenomena.
 Publication:

Physical Review D
 Pub Date:
 February 2014
 DOI:
 10.1103/PhysRevD.89.044024
 arXiv:
 arXiv:1310.4481
 Bibcode:
 2014PhRvD..89d4024P
 Keywords:

 04.25.g;
 04.25.D;
 04.30.w;
 Approximation methods;
 equations of motion;
 Numerical relativity;
 Gravitational waves: theory;
 General Relativity and Quantum Cosmology;
 Astrophysics  High Energy Astrophysical Phenomena
 EPrint:
 17 pages, 20 figures