Accreting isolated neutron stars

Accretion of interstellar material by a magnetized, slowly rotating isolated neutron star is discussed. We show that the average persistent X-ray luminosity of these objects is unlikely to exceed 4x10^26 erg/s. They can also appear as X-ray bursters with the burst duration of ~30 minutes and repetition time of \~10^5 yr. This indicates that the number of the accreting isolated neutron stars which could be observed with recent X-ray missions is a few orders of magnitude smaller than that previously estimated. Our findings argue against models in which the magnetic field of neutron stars is assumed to decay exponentially on a time scale shorter than 500 Myr.