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 a rather simplified but physically oriented three-dimensional magnetar emission model, STEMS3D, to allow spectral investigations up to 100 keV. We then applied our model to the broadband 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 the 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 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.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2015
- DOI:
- 10.1088/0004-637X/815/1/15
- arXiv:
- arXiv:1511.06614
- Bibcode:
- 2015ApJ...815...15W
- Keywords:
-
- magnetic fields;
- pulsars: individual: 4U 0142+61;
- 1E 1841–045;
- radiation mechanisms: non-thermal;
- stars: neutron;
- X-rays: stars;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 8 pages, 3 figures, 2 Tables, ApJ in press