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Published December 10, 2015 | public
Journal Article

Broadband X-ray Spectral Investigations of Magnetars, 4U 0142+61, 1E 1841-045, 1E 2259+586, and 1E 1048.1-5937

Abstract

We have generated an extended version of rather simplified but physically oriented three-dimensional magnetar emission model, STEMS3D, to allow spectral investigations up to 100 keV. We have then applied it to the broadband spectral spectra of four magnetars: 4U 0142+61, 1E 1841-045, 1E 2259+586 and 1E 1048.1-5937, using data collected with Swift/XRT or XMM-Newton in soft X-rays, and Nuclear Spectroscopic Telescope Array in the hard X-ray band. We found that the hard X-ray emission of 4U 0142+61 was spectrally hard compared to the earlier detections, indicating that the source was likely in a transition to or from a harder state. We find that the surface properties of the four magnetars are consistent with what we have obtained using only the soft X-ray data with STEMS3D, implying that our physically motivated magnetar emission model is a robust tool. Based on our broadband spectral investigations, we conclude that resonant scattering of the surface photons in the magnetosphere alone cannot account for the hard X-ray emission in magnetars; therefore, an additional non-thermal process, or a population of relativistic electrons is required. We also discuss the implication of the non-detection of persistent hard X-ray emission in 1E 1048.1-5937.

Additional Information

© 2015. The American Astronomical Society. Received 2015 June 22; accepted 2015 October 21; published 2015 December 2. We thank the referee for helpful suggestions and comments. We thank Feryal Özel for providing the highly magnetized NS surface emission code. S.S.W. is supported by the Scientific and Technological Research Council of Turkey (TÜBİTAK) and EC-FP7 Marie Curie Actions-People-COFUND Brain Circulation Scheme (2236).

Additional details

Created:
August 22, 2023
Modified:
October 17, 2023