Neutron star's initial spin period distribution

Abstract

We analyse different possibilities to explain the wide initial spin period distribution of radio pulsars presented by Noutsos et al. With a population synthesis modelling, we demonstrate that magnetic field decay can be used to interpret the difference between the recent results by Noutsos et al and those by Popov and Turolla, where a much younger population of neutron stars associated with supernova remnants with known ages has been studied. In particular, an exponential field decay with Τ mag = 5 Myr can produce a 'tail' in the reconstructed initial spin period distribution up to P0 > 1 s starting with a standard Gaussian with P0 = 0.3 s and σ = 0.15 s. Another option to explain the difference between initial spin period distributions from Noutsos et al. and Popov and Turolla - the emerging magnetic field - is also briefly discussed. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.