Gravitational waves from an accreting neutron star with a magnetic mountain

Abstract

We calculate the amplitude of gravitational waves from a neutron star accreting symmetrically at its magnetic poles. The magnetic field, which is compressed into an equatorial belt during accretion, confines accreted matter in a mountain at the magnetic pole, producing gravitational waves. We compute hydromagnetic equilibria and the corresponding quadrupole moment as a function of the accreted mass, Ma, finding the polarization‐ and orientation‐ averaged wave strain at Earth to be hc = 6.3 × 10−25(Ma/10−5M⊙)(f/0.6kHz)2(d/1kpc)−1 for a range of conditions, where f is the wave frequency and d is the distance to the source. This is ∼ 102 times greater than previous estimates, which failed to tr..