The Astrophysical Journal (Jan 2024)

X-Ray Polarization of the Black Hole X-Ray Binary 4U 1630–47 Challenges the Standard Thin Accretion Disk Scenario

  • Ajay Ratheesh,
  • Michal Dovčiak,
  • Henric Krawczynski,
  • Jakub Podgorný,
  • Lorenzo Marra,
  • Alexandra Veledina,
  • Valery F. Suleimanov,
  • Nicole Rodriguez Cavero,
  • James F. Steiner,
  • Jiří Svoboda,
  • Andrea Marinucci,
  • Stefano Bianchi,
  • Michela Negro,
  • Giorgio Matt,
  • Francesco Tombesi,
  • Juri Poutanen,
  • Adam Ingram,
  • Roberto Taverna,
  • Andrew West,
  • Vladimir Karas,
  • Francesco Ursini,
  • Paolo Soffitta,
  • Fiamma Capitanio,
  • Domenico Viscolo,
  • Alberto Manfreda,
  • Fabio Muleri,
  • Maxime Parra,
  • Banafsheh Beheshtipour,
  • Sohee Chun,
  • Nicolò Cibrario,
  • Niccolò Di Lalla,
  • Sergio Fabiani,
  • Kun Hu,
  • Philip Kaaret,
  • Vladislav Loktev,
  • Romana Mikušincová,
  • Tsunefumi Mizuno,
  • Nicola Omodei,
  • Pierre-Olivier Petrucci,
  • Simonetta Puccetti,
  • John Rankin,
  • Silvia Zane,
  • Sixuan 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,
  • Enrico Costa,
  • Alessandra De Rosa,
  • Ettore Del Monte,
  • Laura Di Gesu,
  • Alessandro Di Marco,
  • Immacolata Donnarumma,
  • Victor Doroshenko,
  • Steven R. Ehlert,
  • Teruaki Enoto,
  • Yuri Evangelista,
  • Riccardo Ferrazzoli,
  • Javier A. Garcia,
  • Shuichi Gunji,
  • Kiyoshi Hayashida,
  • Jeremy Heyl,
  • Wataru Iwakiri,
  • Svetlana G. Jorstad,
  • Fabian Kislat,
  • Takao Kitaguchi,
  • Jeffery J. Kolodziejczak,
  • Fabio La Monaca,
  • Luca Latronico,
  • Ioannis Liodakis,
  • Simone Maldera,
  • Frédéric Marin,
  • Alan P. Marscher,
  • Herman L. Marshall,
  • Francesco Massaro,
  • Ikuyuki Mitsuishi,
  • Stephen C.-Y. Ng,
  • Stephen L. O’Dell,
  • Chiara Oppedisano,
  • Alessandro Papitto,
  • George G. Pavlov,
  • Abel L. Peirson,
  • Matteo Perri,
  • Melissa Pesce-Rollins,
  • Maura Pilia,
  • Andrea Possenti,
  • Brian D. Ramsey,
  • Oliver J. Roberts,
  • Roger W. Romani,
  • Carmelo Sgrò,
  • Patrick Slane,
  • Gloria Spandre,
  • Douglas A. Swartz,
  • Toru Tamagawa,
  • Fabrizio Tavecchio,
  • Yuzuru Tawara,
  • Allyn F. Tennant,
  • Nicholas E. Thomas,
  • Alessio Trois,
  • Sergey S. Tsygankov,
  • Roberto Turolla,
  • Jacco Vink,
  • Martin C. Weisskopf,
  • Kinwah Wu,
  • Fei Xie

DOI
https://doi.org/10.3847/1538-4357/ad226e
Journal volume & issue
Vol. 964, no. 1
p. 77

Abstract

Read online

A large energy-dependent X-ray polarization degree is detected by the Imaging X-ray Polarimetry Explorer (IXPE) in the high-soft emission state of the black hole X-ray binary 4U 1630–47. The highly significant detection (at ≈50 σ confidence level) of an unexpectedly high polarization, rising from ∼6% at 2 keV to ∼10% at 8 keV, cannot be easily reconciled with standard models of thin accretion disks. In this work, we compare the predictions of different theoretical models with the IXPE data and conclude that the observed polarization properties are compatible with a scenario in which matter accretes onto the black hole through a thin disk covered by a partially ionized atmosphere flowing away at mildly relativistic velocities.

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