A BEPPOSAX OBSERVATION OF THE X-RAY PULSAR 1E-2259-1.0 (CTB-109)(586 AND THE SUPERNOVA REMNANT G109.1)

The 7 s X-ray pulsar 1E 2259+586 and the super nova remnant (SNR) G109 .1-1.0 (CTB 109) were observed by BeppoSAX in 1996 November. The pulse period of 6.978914 +/- 0.000006 s implies that 1E 2259+586 continues its near constant spin-down trend. The 0.5-10 keV pulse shape is chara cterized by a double peaked profile, with the amplitude of the second peak similar to 50% of that of the main peak. The pulse profile does n ot exhibit any strong energy dependence. We confirm the ASCA discovery of an additional low-energy spectral component from 1E 2259+586. This can best be modeled as a 0.44 keV blackbody, but we cannot exclude th at some, or all, of this emission arises from the part of the SNR that lies within the pulsar's extraction region. The spectrum of G109.1-1. 0 is well fit with a non-equilibrium ionization plasma model with a be st-fit temperature of 0.95 keV. The derived mass for the X-ray emittin g plasma (similar to 15-20 M.) and its near cosmic abundances imply th at the X-ray emission comes mainly from mildly enriched, swept-up circ umstellar material. The spectrum is strongly out of equilibrium with a n ionization age of only 3000 yr. This age is in good agreement with t hat derived from hydrodynamic simulations of the SNR using the above X -ray temperature.