General-relativistic electromagnetic fields around a slowly rotating neutron star: Time-dependent pseudo-spectral simulations

Abstract

Pulsars are believed to lose their rotational kinetic energy primarily by a large-amplitude low-frequency electromagnetic wave which is eventually converted into particle creation, acceleration and followed by a broad-band radiation spectrum. To date, there exist no detailed calculation of the exact spin-down luminosity with respect to the neutron star magnetic moment and spin frequency, including general-relativistic effects. Estimates are usually given according to the flat space-time magnetodipole formula. This paper pursues our effort to look for accurate solutions of the general-relativistic electromagnetic field around a slowly rotating magnetized neutron star. In a previous work, we already found approximate stationary solutions to this problem. Here, we address again this problem but using a more general approach. We indeed solve the full set of time-dependent Maxwell equations in a curved vacuum space-time following the 3+1 formalism. The numerical code is based on our pseudo-spectral method exposed in a previous paper for flat space-time. We adapted it to an arbitrary fixed background metric. Stationary solutions are readily obtained and compared to semi-analytical calculations. © 2014 The Author Published by Oxford University Press on behalf of the Royal Astronomical Society.