Magnetars are neutron stars with ultrastrong magnetic fields, which can be observed in x-rays. Polarization measurements could provide information on their magnetic fields and surface properties. We observed polarized x-rays from the magnetar 4U 0142+61 using the Imaging X-ray Polarimetry Explorer and found a linear polarization degree of 13.5 ± 0.8% averaged over the 2- to 8-kilo-electron volt band. The polarization changes with energy: The degree is 15.0 ± 1.0% at 2 to 4 kilo-electron volts, drops below the instrumental sensitivity ~4 to 5 kilo-electron volts, and rises to 35.2 ± 7.1% at 5.5 to 8 kilo-electron volts. The polarization angle also changes by 90° at ~4 to 5 kilo-electron volts. These results are consistent with a model in which thermal radiation from the magnetar surface is reprocessed by scattering off charged particles in the magnetosphere.

Taverna, R., Turolla, R., Muleri, F., Heyl, J., Zane, S., Baldini, L., et al. (2022). Polarized x-rays from a magnetar. SCIENCE, 378(6620), 646-650 [10.1126/science.add0080].

Polarized x-rays from a magnetar

Tombesi, Francesco;
2022-11-11

Abstract

Magnetars are neutron stars with ultrastrong magnetic fields, which can be observed in x-rays. Polarization measurements could provide information on their magnetic fields and surface properties. We observed polarized x-rays from the magnetar 4U 0142+61 using the Imaging X-ray Polarimetry Explorer and found a linear polarization degree of 13.5 ± 0.8% averaged over the 2- to 8-kilo-electron volt band. The polarization changes with energy: The degree is 15.0 ± 1.0% at 2 to 4 kilo-electron volts, drops below the instrumental sensitivity ~4 to 5 kilo-electron volts, and rises to 35.2 ± 7.1% at 5.5 to 8 kilo-electron volts. The polarization angle also changes by 90° at ~4 to 5 kilo-electron volts. These results are consistent with a model in which thermal radiation from the magnetar surface is reprocessed by scattering off charged particles in the magnetosphere.
11-nov-2022
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore FIS/05 - ASTRONOMIA E ASTROFISICA
English
Taverna, R., Turolla, R., Muleri, F., Heyl, J., Zane, S., Baldini, L., et al. (2022). Polarized x-rays from a magnetar. SCIENCE, 378(6620), 646-650 [10.1126/science.add0080].
Taverna, R; Turolla, R; Muleri, F; Heyl, J; Zane, S; Baldini, L; González-Caniulef, D; Bachetti, M; Rankin, J; Caiazzo, I; Di Lalla, N; Doroshenko, V...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/314249
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