X-ray and Infrared Enhancement of Anomalous X-ray Pulsar

The long-term ( 1.5 yr) X-ray enhancement and the accompanying infrared enhancement light curves of the anomalous X-ray pulsar 1E 2259+586 following the major bursting epoch can be accounted for by the relaxation of a fallback disk that has been pushed back by a gamma-ray flare. The required burst energy estimated from the results of our model fits is low enough for such a burst to have remained below the detection limits. We find that an irradiated disk model with a low irradiation efficiency is in good agreement with both X-ray and infrared data. Nonirradiated disk models also give a good fit to the X-ray light curve, but are not consistent with the infrared data for the first week of the enhancement. Subject headings: accretion, accretion disks — pulsars: individual (1E 2259+586) — stars: neutron — X-rays: bursts