Abstract
Recent observations with the Imaging X-ray Polarimetry Explorer (IXPE) of two anomalous X-ray pulsars provided evidence that X-ray emission from magnetar sources is strongly polarized. Here we report on the joint IXPE and XMM-Newton observations of the soft γ-repeater SGR 1806-20. The spectral and timing properties of SGR 1806-20 derived from XMM-Newton data are in broad agreement with previous measurements; however, we found the source at an all-time low persistent flux level. No significant polarization was measured apart from the 4-5 keV energy range, where a probable detection with PD = 31.6% ± 10.5% and PA = − 17 .° 6 − 15 .° 0 + 15 .° 5 was obtained. The resulting polarization signal, together with the upper limits we derive at lower and higher energies (2-4 and 5-8 keV, respectively), is compatible with a picture in which thermal radiation from the condensed star surface is reprocessed by resonant Compton scattering in the magnetosphere, similar to what was proposed for the bright magnetar 4U 0142+61.
Original language | English (US) |
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Article number | 88 |
Journal | Astrophysical Journal |
Volume | 954 |
Issue number | 1 |
DOIs | |
State | Published - Sep 1 2023 |
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science