The Astrophysical Journal (Jan 2023)

First X-Ray Polarization Measurement Confirms the Low Black Hole Spin in LMC X-3

  • Jiří Svoboda,
  • Michal Dovčiak,
  • James F. Steiner,
  • Fabio Muleri,
  • Adam Ingram,
  • Anastasiya Yilmaz,
  • Nicole Rodriguez Cavero,
  • Lorenzo Marra,
  • Juri Poutanen,
  • Alexandra Veledina,
  • Mehrnoosh Rahbardar Mojaver,
  • Stefano Bianchi,
  • Javier A. García,
  • Philip Kaaret,
  • Henric Krawczynski,
  • Giorgio Matt,
  • Jakub Podgorný,
  • Martin C. Weisskopf,
  • Fabian Kislat,
  • Pierre-Olivier Petrucci,
  • Maimouna Brigitte,
  • Michal Bursa,
  • Sergio Fabiani,
  • Kun Hu,
  • Sohee Chun,
  • Guglielmo Mastroserio,
  • Romana Mikus̆incová,
  • Ajay Ratheesh,
  • Roger W. Romani,
  • Paolo Soffitta,
  • Francesco Ursini,
  • Silvia Zane,
  • Iván Agudo,
  • Lucio A. Antonelli,
  • Matteo Bachetti,
  • Luca Baldini,
  • Wayne H. Baumgartner,
  • Ronaldo Bellazzini,
  • Stephen D. Bongiorno,
  • Raffaella Bonino,
  • Alessandro Brez,
  • Niccolò Bucciantini,
  • Fiamma Capitanio,
  • Simone Castellano,
  • Elisabetta Cavazzuti,
  • Chien-Ting Chen,
  • Stefano Ciprini,
  • Enrico Costa,
  • 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,
  • Riccardo Ferrazzoli,
  • Shuichi Gunji,
  • Kiyoshi Hayashida,
  • Jeremy Heyl,
  • Wataru Iwakiri,
  • Svetlana G. Jorstad,
  • Vladimír Karas,
  • Takao Kitaguchi,
  • Jeffery J. Kolodziejczak,
  • Fabio La Monaca,
  • Luca Latronico,
  • Ioannis Liodakis,
  • Simone Maldera,
  • Alberto Manfreda,
  • Frédéric Marin,
  • Andrea Marinucci,
  • Alan P. Marscher,
  • Herman L. Marshall,
  • Francesco Massaro,
  • Ikuyuki Mitsuishi,
  • Tsunefumi Mizuno,
  • Michela Negro,
  • Chi-Yung Ng,
  • Stephen L. O’Dell,
  • Nicola Omodei,
  • Chiara Oppedisano,
  • Alessandro Papitto,
  • George G. Pavlov,
  • Abel L. Peirson,
  • Matteo Perri,
  • Melissa Pesce-Rollins,
  • Maura Pilia,
  • Andrea Possenti,
  • Simonetta Puccetti,
  • Brian D. Ramsey,
  • John Rankin,
  • Oliver J. Roberts,
  • Carmelo Sgrò,
  • Patrick Slane,
  • Gloria Spandre,
  • Douglas A. Swartz,
  • Toru Tamagawa,
  • Fabrizio Tavecchio,
  • Roberto Taverna,
  • Yuzuru Tawara,
  • Allyn F. Tennant,
  • Nicholas E. Thomas,
  • Francesco Tombesi,
  • Alessio Trois,
  • Sergey S. Tsygankov,
  • Roberto Turolla,
  • Jacco Vink,
  • Kinwah Wu,
  • Fei Xie

DOI
https://doi.org/10.3847/1538-4357/ad0842
Journal volume & issue
Vol. 960, no. 1
p. 3

Abstract

Read online

X-ray polarization is a powerful tool to investigate the geometry of accreting material around black holes, allowing independent measurements of the black hole spin and orientation of the innermost parts of the accretion disk. We perform X-ray spectropolarimetric analysis of an X-ray binary system in the Large Magellanic Cloud, LMC X-3, that hosts a stellar-mass black hole, known to be persistently accreting since its discovery. We report the first detection of the X-ray polarization in LMC X-3 with the Imaging X-ray Polarimetry Explorer, and find the average polarization degree (PD) of 3.2% ± 0.6% and a constant polarization angle of −42° ± 6° over the 2–8 keV range. Using accompanying spectroscopic observations by NICER, NuSTAR, and the Neil Gehrels Swift observatories, we confirm previous measurements of the black hole spin via the X-ray continuum method, a ≈ 0.2. From polarization analysis only, we found consistent results with low black hole spin, with an upper limit of a < 0.7 at a 90% confidence level. A slight increase in the PD with energy, similar to other black hole X-ray binaries in the soft state, is suggested from the data but with a low statistical significance.

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