Tsygankov, Sergey S;
Doroshenko, Victor;
Mushtukov, Alexander A;
Poutanen, Juri;
Di Marco, Alessandro;
Wu, Jeremy;
La Monaca, Fabio;
... Zane, Silvia; + view all
(2023)
X-ray pulsar GRO J1008−57 as an orthogonal rotator.
Astronomy and Astrophysics: a European journal
, 675
, Article A48. 10.1051/0004-6361/202346134.
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Abstract
X-ray polarimetry is a unique way to probe the geometrical configuration of highly magnetized accreting neutron stars (X-ray pulsars). GRO J1008−57 is the first transient X-ray pulsar observed at two different flux levels by the Imaging X-ray Polarimetry Explorer (IXPE) during its outburst in November 2022. We find the polarization properties of GRO J1008−57 to be independent of its luminosity, with the polarization degree varying between nondetection and about 15% over the pulse phase. Fitting the phase-resolved spectro-polarimetric data with the rotating vector model allowed us to estimate the pulsar inclination (130°, which is in good agreement with the orbital inclination), the position angle (75°) of the pulsar spin axis, and the magnetic obliquity (∼74°). This makes GRO J1008−57 the first confidently identified nearly orthogonal rotator among X-ray pulsars. We discuss our results in the context of the neutron star atmosphere models and theories of the axis alignment of accreting pulsars.
Type: | Article |
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Title: | X-ray pulsar GRO J1008−57 as an orthogonal rotator |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1051/0004-6361/202346134 |
Publisher version: | https://doi.org/10.1051/0004-6361/202346134 |
Language: | English |
Additional information: | © The Authors 2023 Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication. |
Keywords: | accretion / accretion disks / magnetic fields / pulsars: individual: GRO J1008−57 / stars: neutron / X-rays: binaries |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
URI: | https://discovery.ucl.ac.uk/id/eprint/10169616 |
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