Peter den Hartog: Different spectral components revealed in the high-energy pulse profiles of Anomalous X-ray Pulsars

4 AXPs have been detected above 10 keV, 3 with INTEGRAL and 1 with the High Energy X-ray Timing Experiment (HEXTE) aboard the Rossi X-ray Timing Explorer (RXTE). For AXPs 4U 0142+61 and 1 RXS J1708-40 he finds peak energies of 279 keV and 287 keV respectively. Pulsed emission from 1 RXS J1708-40 is observed upto 270 keV. Broadband phase resolved spectroscopy of this source revealed that different components of its pulse profile vary with energy. In only 0.1 in pulse phase the spectrum of the source goes from very hard to very soft. He concludes that the pulsed spectra of AXPs are much more complex than previously thought. Many spectral components are required to explain the pulse shapes of these sources. These observations can be used to test the geometries of the magnetospheres of these sources. If you would like a copy of Peter's thesis, email him at Hartog@sron.nl.