AXPs and X-ray-dim isolated neutron stars: recent XMM-Newton and Chandra results

Abstract

To date more than half a dozen X-ray-dim isolated neutron stars are known. Their X-ray spectra are characterized by soft blackbody-like emission ( kT∼50-120 eV) without indication for harder, non-thermal components. These stars apparently show no radio emission and no association with supernova remnants. Four of them exhibit pulsations in their X-ray flux with periods in the range 8.39-22.7 s. Similar pulse periods were found from AXPs, maybe suggesting evolutionary connections. I will review the recent observational results from X-ray-dim isolated neutron stars obtained by the major X-ray observatories XMM-Newton and Chandra. Spectral and temporal characteristics, inferred luminosities and magnetic field strengths will be compared with those of AXPs.