The Discovery of Rapid Polarization Angle Variation during the 2022 Outburst of XTE J1701-462

The geometry of the Comptonization corona in neutron star low-mass X-ray binaries is still unclear. We conducted time-resolved polarimetric analysis of the archival observations of XTE J1701–462 obtained with the Imaging X-ray Polarimeter Explorer during its 2022 outburst and found that the polariza...

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Bibliographic Details
Main Authors: Qing-Chang Zhao, Hong Li, Lian Tao, Hua Feng
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/adb8cf
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Summary:The geometry of the Comptonization corona in neutron star low-mass X-ray binaries is still unclear. We conducted time-resolved polarimetric analysis of the archival observations of XTE J1701–462 obtained with the Imaging X-ray Polarimeter Explorer during its 2022 outburst and found that the polarization angle (PA) varied significantly with time when the source was in the normal branch, with 67 ^∘  ± 8 ^∘ in the first epoch, −34 ^∘  ± 8 ^∘ in the second, and −58 ^∘  ± 8 ^∘ in the third, last epoch. Meanwhile, the polarization degree remained constant at around 2%, above the minimum detectable polarization at the 99% confidence level (MDP _99 ). The rapid PA variation causes depolarization in the time-averaged data, resulting in a nondetection as reported in the literature. The rapid (intraday) PA variation may suggest that there is a fast transformation of the corona geometry, likely switching from a slab geometry with enhanced disk emission and reflection, to a more vertically extended spreading layer geometry.
ISSN:1538-4357