The Astrophysical Journal Letters (Jan 2024)

NICER, NuSTAR, and Insight-HXMT Views to the Newly Discovered Black Hole X-Ray Binary Swift J1727.8-1613

  • Jing-Qiang Peng,
  • Shu Zhang,
  • Qing-Cang Shui,
  • Shuang-Nan Zhang,
  • Ling-Da Kong,
  • Yu-Peng Chen,
  • Peng-Ju Wang,
  • Long Ji,
  • Jin-Lu Qu,
  • Lian Tao,
  • Ming-Yu Ge,
  • Zhi Chang,
  • Jian Li,
  • Zhao-sheng Li,
  • Zhuo-Li Yu,
  • Zhe Yan

DOI
https://doi.org/10.3847/2041-8213/ad17ca
Journal volume & issue
Vol. 960, no. 2
p. L17

Abstract

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Swift J1727.8–1613 is a black hole X-ray binary newly discovered in 2023. We perform spectral analysis with simultaneous Insight-HXMT, NICER, and NuSTAR observations when the source was approaching the hard intermediate state. Such a joint view reveals an additional hard component apart from the normally observed hard component with reflection in the spectrum, to be distinguished from the usual black hole X-ray binary systems. By including this extra component in the spectrum, we have measured a high spin of ${0.98}_{-0.07}^{+0.02}$ and an inclination of around ${40}_{-0.8}^{+1.2}$ °, which is consistent with NICER results reported before. However, we find that the additional spectral component cannot be exclusively determined due to the model degeneracy. Accordingly, a possible jet/corona configuration is adjusted to account for the spectral fitting with different model trials. The extra component may originate either from a relativistic jet or a jet base/corona underneath a slow jet.

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