First evidence of a cyclotron feature in an anomalous X-ray pulsar
arXiv:astro-ph/0309402 · doi:10.1016/j.nuclphysbps.2004.04.093
Abstract
We report on the results of the longest uninterrupted observation of the Anomalous X-ray Pulsar 1RXS J1708-4009 obtained with the BeppoSAX satellite in August 2001. In the phase-resolved spectrum, corresponding to the rising part of the pulse, we found an absorption-like feature at 8.1 keV (significance level of 4 sigma), most likely due to cyclotron resonant scattering. The centroid energy converts to a magnetic field of 9x10^{11} G and 1.6x10^{15} G in the case of electrons and protons, respectively. If confirmed, this would be the first detection of a cyclotron feature in the spectrum of an anomalous X-ray pulsar. We discuss here the results also in ligh of recent theoretical models for these class of sources.
talk at the Restless High Energy Universe in Amsterdam; to be published in Elsevier in Nucl. Physics B. Suppl. Ser