On the role of magnetic fields into the dynamics and gravitational wave emission of binary neutron stars

TL;DR

This paper models magnetic interactions in binary neutron star systems and assesses their impact on gravitational wave signals, finding effects comparable to second post-Newtonian corrections for magnetic fields around 10^16 G.

Contribution

It introduces a dipole magnetic interaction model into the inspiral dynamics and provides explicit formulas for magnetic effects on gravitational waveforms.

Findings

Magnetic effects are comparable to 2PN corrections for B ~ 10^16 G.

Magnetic interactions influence the gravitational wave phase and amplitude.

Magnetic effects could be detectable with current gravitational wave observatories.

Abstract

Modelling as a dipole the magnetic interaction of a binary system of neutron stars, we are able to include the magnetic effects in the Newtonian and in the inspiral dynamics of the system using an equivalent one-body description. Furthermore, in the inspiral stage we determine the role of the magnetic interaction in the waveforms generated by the system and obtain explicit formulas for the decrease in the separation of the stars, the time to reach a minimal radius, the gravitational luminosity and the change of gravitational wave frequency, all this within the quadrupole approximation. For the magnitude of the magnetic field that is consider to exist in these binaries $\sim 10^{16} {\rm G}$ we are able to show that its effect on the observable quantities is of the order of the 2PN correction, already close to the detection range of the gravitational waves observatories. %} We also discuss cases in which the magnetic field could have a more significant influence.