2024/11/18 by QingChang Zhao, Hongye Li, Zhao, QingChang +5
Physics and Astronomy · Mathematics · #Pulsars and Gravitational Waves Research #Statistical and numerical algorithms #Gamma-ray bursts and supernovae
paper · pdf · doi:10.48550/arxiv.2411.11352
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 (NB), 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 (MDP99). The rapid PA variation causes depolarization in the time-averaged data, resulting in a nondetection as reported in the literature. The rapid (intra-day) 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.