DOI: 10.1093/mnras/stad2601 ISSN:

Detection of significant X-ray polarization from transient NS-LMXB XTE J1701−462 with IXPE and its implication on the coronal geometry

Kiran M Jayasurya, Vivek K Agrawal, Rwitika Chatterjee
  • Space and Planetary Science
  • Astronomy and Astrophysics


In this paper, we performed a spectro-polarimetric analysis of the transient NS-LMXB XTE J1701 − 462 using IXPE, NICER and NuSTAR data during its 2022 outburst. We report significant detection of energy-dependent polarization in the X-ray signal from the source on 2022 September 29 in the 2–4 keV, 4–8 keV and 2–8 keV energy bands with a polarization degree of 3.9 ± 0.3%, 5.5 ± 0.6% and 4.5 ± 0.4%, respectively. The polarization angle in the overall 2–8 keV band was ∼143○ ± 2○. The spectra were modelled using a combination of thermal emission from an accretion disc, Comptonized emission from a hot electron plasma (or corona) and a Gaussian line. From spectro-polarimetric analysis, the polarization degree due to the disc emission had an upper limit of ∼ 11.5%, and that of the Comptonized emission was constrained at 7.7 ± 2.5% (at the 3σ level). The results suggest that the Comptonized component probably originates from a spreading-layer/boundary-layer above the neutron star surface. IXPE observation of the source on 2022 October 8 does not show significant polarization which can be attributed to a weakening of the coronal Comptonized emission. The implication of these results are discussed.

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