Suzaku Observation of the Anomalous X-Ray Pulsar 1E 1841−045

Abstract

Abstract We report on the results of a Suzaku observation of the anomalous X-ray pulsar (AXP) 1E 1841$-$045 at the center of the supernova remnant Kes 73. We confirmed that the energy-dependent spectral models obtained by previous separate observations were also satisfied over a wide energy range from 0.4 to $\sim$70 keV, simultaneously. Here, the models below $\sim$10 keV were a combination of blackbody (BB) and power-law (PL) functions, or of two BBs with different temperatures at 0.6–7.0 keV (Morii et al. 2003, PASJ, 55, L45), and that above $\sim$20 keV was a PL function (Kuiper et al. 2004, ApJ, 613, 1173). The combination BB $+$ PL $+$ PL was found to best represent the phase-averaged spectrum. Phase-resolved spectroscopy indicated the existence of two emission regions, one with a thermal and the other with a non-thermal nature. The combination BB $+$ BB $+$ PL was also found to represent the phase-averaged spectrum well. However, we found that this model is physically unacceptable due to an excessively large area of the emission region of the blackbody. Nonetheless, we found that the temperatures and radii of the two blackbody components showed moderate correlations in the phase-resolved spectra. The fact that the same correlations have been observed between the phase-averaged spectra of various magnetars (Nakagawa et al. 2009, PASJ, 61, 109) suggests that a self-similar function can approximate the intrinsic energy spectra of magnetars below $\sim$10 keV.