Samenvatting

The observed persistent soft X-ray spectra (0.5 - 10 keV) of anomalous Xray
pulsars (AXPs) can be explained by the magnetar model (Woods and
Thompson et al., 2002 [3]) where the emission is powered by the decay of
an extreme high magnetic eld ( 1014 G). Because these spectra are relatively soft, measurements above 10 keV were not expected to detect any hard X-rays. Surprisingly, observations with the Rossi X-ray Timing Explorer (RXTE) and INTEGRAL have shown that AXP sources can have so-called `hard spectral tails' above 20 keV. In this research additional (not used in earlier spectral timing studies) data from RXTE of AXP 1E2259+586 are analyzed in the high-energy range (2 - 250 keV) to con rm or disprove the found indications by Kuiper et al. (2006, [4]) of the same hard spectral tail. In their work they nd for other AXPs evidence for pulsed emission above 10 keV and present strong indications for a similar hard spectral tail in 1E2259+586. To obtain the pulse pro les in the high-energy range, timing models of the pulsar's rotational behaviour have been constructed for the 2 - 4 keV energy band, in which the signal is strong. Analyzing RXTEs Proportional Counter Array (PCA) data from observations performed between October 28, 2003 and December 29, 2011, three di erent timing models have been constructed to describe the rotational behaviour during this period. The reason for this is the occurrence of two glitches (a star quake with an abrupt change in rotation frequency) at MJD 54190 3.5 d and 54881. Using these newly derived timing models in the subsequent pulse phase folding analysis for the new observational data yielded again a strong indication (at a 3.3 level) for pulsed emission from 1E2259+586 in the 16.3 - 32.0 keV band. However, a combination of the old and newly analyzed data covering the full RXTE mission period provides no decisive answer to the shape of the pulsed signal above 16 keV. Future observations with more sensitive instruments covering the hard X-ray/soft gamma-ray band like NuSTAR (3 - 80 keV) are required to reach rm conclusions about the existence of a hard spectral tail of 1E2259+586.