Gravitomagnetic tidal effects in gravitational waves from neutron star binaries
Abstract
Gravitational waves emitted by coalescing binary systems containing neutron stars (or other compact objects) carry signatures of the stars' internal equation of state, notably, through the influence of tidal deformations during the binary's inspiral stage. While the leadingorder tidal effects for postNewtonian binaries of compact bodies in general relativity are due to the bodies' massquadrupole moments induced by gravitoelectric tidal fields, we consider here the leading effects due to currentquadrupole moments induced by gravitomagnetic tidal fields. We employ an effective action approach to determine the nearzone gravitational field and the conservative orbital dynamics, initially allowing for arbitrary (not just tidally induced) current quadrupoles; our approach significantly reduces the complexity of the calculation compared to previous derivations of the conservative dynamics for arbitrary multipoles. We finally compute the leading contributions from gravitomagnetic tides to the phase and (for the first time) the mode amplitudes of the gravitational waves from a quasicircular binary inspiral, given in terms of the bodies' quadrupolar gravitomagnetic tidal Love numbers (tidal linear response coefficients in an adiabatic approximation). In the phase, gravitomagnetic tides are suppressed by one postNewtonian order relative to gravitoelectric ones, but this is not always the case for the mode amplitudes. In the (ℓ,m )=(2 ,1 ) and (3,2) modes, for example, they appear at the same leading orders.
 Publication:

Physical Review D
 Pub Date:
 March 2020
 DOI:
 10.1103/PhysRevD.101.064003
 arXiv:
 arXiv:1805.07266
 Bibcode:
 2020PhRvD.101f4003B
 Keywords:

 General Relativity and Quantum Cosmology
 EPrint:
 15 pages