The influence of magnetic fields on the gravitational-wave emission from binary neutron stars

Using accurate and fully general-relativistic simulations we assess the effect that magnetic fields have on the gravitational-wave emission produced during the inspiral and merger of magnetized neutron stars. In particular, we show that magnetic fields have an impact after the merger, because amplified by a Kelvin-Helmholtz instability, but also during the inspiral, because the magnetic tension reduces the stellar tidal deformation for extremely large initial magnetic fields, B_0>10^{17}G. We quantify the influence of magnetic fields by computing the overlap, O, between the waveforms produced during the inspiral by magnetized and unmagnetized binaries. We find that for B_0~10^{17}G, O<0.76 for stars with mass M~1.4Msun, dropping to O