The Astrophysical Journal Letters (Jan 2023)

Discovery of X-Ray Polarization from the Black Hole Transient Swift J1727.8−1613

  • Alexandra Veledina,
  • Fabio Muleri,
  • Michal Dovčiak,
  • Juri Poutanen,
  • Ajay Ratheesh,
  • Fiamma Capitanio,
  • Giorgio Matt,
  • Paolo Soffitta,
  • Allyn F. Tennant,
  • Michela Negro,
  • Philip Kaaret,
  • Enrico Costa,
  • Adam Ingram,
  • Jiří Svoboda,
  • Henric Krawczynski,
  • Stefano Bianchi,
  • James F. Steiner,
  • Javier A. García,
  • Vadim Kravtsov,
  • Anagha P. Nitindala,
  • Melissa Ewing,
  • Guglielmo Mastroserio,
  • Andrea Marinucci,
  • Francesco Ursini,
  • Francesco Tombesi,
  • Sergey S. Tsygankov,
  • Yi-Jung Yang,
  • Martin C. Weisskopf,
  • Sergei A. Trushkin,
  • Elise Egron,
  • Maria Noemi Iacolina,
  • Maura Pilia,
  • Lorenzo Marra,
  • Romana Mikušincová,
  • Edward Nathan,
  • Maxime Parra,
  • Pierre-Olivier Petrucci,
  • Jakub Podgorný,
  • Stefano Tugliani,
  • Silvia Zane,
  • Wenda Zhang,
  • Iván Agudo,
  • Lucio A. Antonelli,
  • Matteo Bachetti,
  • Luca Baldini,
  • Wayne H. Baumgartner,
  • Ronaldo Bellazzini,
  • Stephen D. Bongiorno,
  • Raffaella Bonino,
  • Alessandro Brez,
  • Niccolò Bucciantini,
  • Simone Castellano,
  • Elisabetta Cavazzuti,
  • Chien-Ting Chen,
  • Stefano Ciprini,
  • Alessandra De Rosa,
  • Ettore Del Monte,
  • Laura Di Gesu,
  • Niccolò Di Lalla,
  • Alessandro Di Marco,
  • Immacolata Donnarumma,
  • Victor Doroshenko,
  • Steven R. Ehlert,
  • Teruaki Enoto,
  • Yuri Evangelista,
  • Sergio Fabiani,
  • Riccardo Ferrazzoli,
  • Shuichi Gunji,
  • Kiyoshi Hayashida,
  • Jeremy Heyl,
  • Wataru Iwakiri,
  • Svetlana G. Jorstad,
  • Vladimir Karas,
  • Fabian Kislat,
  • Takao Kitaguchi,
  • Jeffery J. Kolodziejczak,
  • Fabio La Monaca,
  • Luca Latronico,
  • Ioannis Liodakis,
  • Simone Maldera,
  • Alberto Manfreda,
  • Frédéric Marin,
  • Alan P. Marscher,
  • Herman L. Marshall,
  • Francesco Massaro,
  • Ikuyuki Mitsuishi,
  • Tsunefumi Mizuno,
  • Chi-Yung Ng,
  • Stephen L. O’Dell,
  • Nicola Omodei,
  • Chiara Oppedisano,
  • Alessandro Papitto,
  • George G. Pavlov,
  • Abel L. Peirson,
  • Matteo Perri,
  • Melissa Pesce-Rollins,
  • Andrea Possenti,
  • Simonetta Puccetti,
  • Brian D. Ramsey,
  • John Rankin,
  • Oliver J. Roberts,
  • Roger W. Romani,
  • Carmelo Sgrò,
  • Patrick Slane,
  • Gloria Spandre,
  • Douglas A. Swartz,
  • Toru Tamagawa,
  • Fabrizio Tavecchio,
  • Roberto Taverna,
  • Yuzuru Tawara,
  • Nicholas E. Thomas,
  • Alessio Trois,
  • Roberto Turolla,
  • Jacco Vink,
  • Kinwah Wu,
  • Fei Xie

DOI
https://doi.org/10.3847/2041-8213/ad0781
Journal volume & issue
Vol. 958, no. 1
p. L16

Abstract

Read online

We report the first detection of the X-ray polarization of the bright transient Swift J1727.8−1613 with the Imaging X-ray Polarimetry Explorer. The observation was performed at the beginning of the 2023 discovery outburst, when the source resided in the bright hard state. We find a time- and energy-averaged polarization degree of 4.1% ± 0.2% and a polarization angle of 2.°2 ± 1.°3 (errors at 68% confidence level; this translates to ∼20 σ significance of the polarization detection). This finding suggests that the hot corona emitting the bulk of the detected X-rays is elongated, rather than spherical. The X-ray polarization angle is consistent with that found in submillimeter wavelengths. Since the submillimeter polarization was found to be aligned with the jet direction in other X-ray binaries, this indicates that the corona is elongated orthogonal to the jet.

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