The Astrophysical Journal (Jan 2024)

First Detection of Polarization in X-Rays for PSR B0540-69 and Its Nebula

  • Fei Xie,
  • Josephine Wong,
  • Fabio La Monaca,
  • Roger W. Romani,
  • Jeremy Heyl,
  • Philip Kaaret,
  • Alessandro Di Marco,
  • Niccolò Bucciantini,
  • Kuan Liu,
  • Chi-Yung Ng,
  • Niccolò Di Lalla,
  • Martin C. Weisskopf,
  • Enrico Costa,
  • Paolo Soffitta,
  • Fabio Muleri,
  • Matteo Bachetti,
  • Maura Pilia,
  • John Rankin,
  • Sergio Fabiani,
  • Iván Agudo,
  • Lucio A. Antonelli,
  • Luca Baldini,
  • Wayne H. Baumgartner,
  • Ronaldo Bellazzini,
  • Stefano Bianchi,
  • Stephen D. Bongiorno,
  • Raffaella Bonino,
  • Alessandro Brez,
  • Fiamma Capitanio,
  • Simone Castellano,
  • Elisabetta Cavazzuti,
  • Chien-Ting Chen,
  • Stefano Ciprini,
  • Alessandra De Rosa,
  • Ettore Del Monte,
  • Laura Di Gesu,
  • Immacolata Donnarumma,
  • Victor Doroshenko,
  • Michal Dovčiak,
  • Steven R. Ehlert,
  • Teruaki Enoto,
  • Yuri Evangelista,
  • Riccardo Ferrazzoli,
  • Javier A. Garcia,
  • Shuichi Gunji,
  • Kiyoshi Hayashida,
  • Wataru Iwakiri,
  • Svetlana G. Jorstad,
  • Vladimir Karas,
  • Fabian Kislat,
  • Takao Kitaguchi,
  • Jeffery J. Kolodziejczak,
  • Henric Krawczynski,
  • Luca Latronico,
  • Ioannis Liodakis,
  • Simone Maldera,
  • Alberto Manfreda,
  • Frédéric Marin,
  • Andrea Marinucci,
  • Alan P. Marscher,
  • Herman L. Marshall,
  • Francesco Massaro,
  • Giorgio Matt,
  • Ikuyuki Mitsuishi,
  • Tsunefumi Mizuno,
  • Michela Negro,
  • Stephen L. O’Dell,
  • Nicola Omodei,
  • Chiara Oppedisano,
  • Alessandro Papitto,
  • George G. Pavlov,
  • Abel L. Peirson,
  • Matteo Perri,
  • Melissa Pesce-Rollins,
  • Pierre-Olivier Petrucci,
  • Andrea Possenti,
  • Juri Poutanen,
  • Simonetta Puccetti,
  • Brian D. Ramsey,
  • Ajay Ratheesh,
  • 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,
  • Silvia Zane,
  • IXPE Collaboration,
  • Zorawar Wadiasingh,
  • Wynn C. G. Ho,
  • Alice K. Harding,
  • Keith C. Gendreau,
  • Zaven Arzoumanian

DOI
https://doi.org/10.3847/1538-4357/ad17ba
Journal volume & issue
Vol. 962, no. 1
p. 92

Abstract

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We report on X-ray polarization measurements of the extragalactic Crab-like PSR B0540-69 and its Pulsar Wind Nebula (PWN) in the Large Magellanic Cloud, using a ∼850 ks Imaging X-ray Polarimetry Explorer (IXPE) exposure. The PWN is unresolved by IXPE. No statistically significant polarization is detected for the image-averaged data, giving a 99% confidence polarization upper limit (MDP _99 ) of 5.3% in the 2–8 keV energy range. However, a phase-resolved analysis detects polarization for both the nebula and pulsar in the 4–6 keV energy range. For the PWN defined as the off-pulse phases, the polarization degree (PD) of (24.5 ± 5.3)% and polarization angle (PA) of (78.1 ± 6.2)° is detected at 4.6 σ significance level, consistent with the PA observed in the optical band. In a single on-pulse window, a hint of polarization is measured at 3.8 σ with PD of (50.0 ± 13.1)% and PA of (6.2 ± 7.4)°. A “simultaneous” PSR/PWN analysis finds two bins at the edges of the pulse exceeding 3 σ PD significance, with PD of (68 ± 20)% and (62 ± 20)%; intervening bins at 2–3 σ significance have lower PD, hinting at additional polarization structure.

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