Polarized X-ray Radiation from Magnetars and X-ray Pulsars

ORAL

Abstract

With the launch of IXPE at the end of 2021, we have entered the era of X-ray polarization. IXPE is more than one thousand times more sensitive that previous observations giving us “first (polarized) light” images of hundreds of X-ray sources. Looking as these objects in an essentially new way for the very first time has been exhilarating. I will focus in particular on the observations of magnetar and accreting X-ray pulsars.

Magnetars harbour the strongest magnetic fields in the Universe. IXPE observations of magnetars have probed the properties of the surface and magnetospheres of these objects in unprecedented detail. In particular IXPE observations indicate that the surface layers of this objects may be solid or liquid (not gaseous even though their temperatures exceed one million Kelvin). Observations also provide an independent verification of magnetic fields near the surface of these objects exceeding ten gigatesla and the role of resonant cyclotron scattering in the processing of their emission.

Accreting pulsars which despite complicated magnetic field and emission geometries with only a single exception exhibit very simple changes in the polarization direction as the stars rotate. This straightforward evolution with spin results from the first (yet still unverified) prediction of QED that a magnetic field even in vacuum induces an index of refraction: vacuum birefringence. The observations of the prototypical X-ray pulsar Hercules X-1 reveal the interior of the neutron star, while observations of the supercritical accretor LS V +44 17/RX J0440.9+4431 show complexity of the emitting accretion flow can produce more complicated polarization patterns.

*The Imaging X-ray Polarimetry Explorer (IXPE) is a joint US and Italian mission. The US contribution is supported by the National Aeronautics and Space Administration (NASA) and led and managed by its Marshall Space Flight Center (MSFC), with industry partner Ball Aerospace (contract NNM15AA18C). The Italian contribution is supported by the Italian Space Agency (Agenzia Spaziale Italiana, ASI) through contract ASI-ASI-OHBI-2022-13-I.0, agreements ASI-INAF-2022-19-HH.0 and ASI-INFN-2017.13-H0, and its Space Science Data Center (SSDC) with agreements ASI-INAF-2022-14-HH.0 and ASI-INFN 2021-43-HH.0, and by the Istituto Nazionale di Astrofisica (INAF) and the Istituto Nazionale di Fisica Nucleare (INFN) in Italy.This research used data products provided by the IXPE Team (MSFC, SSDC, INAF, and INFN) and distributed with additional software tools by the High-Energy Astrophysics Science Archive Research Center (HEASARC), at NASA Goddard Space Flight Center (GSFC). JH acknowledges support from the Natural Sciences and Engineering Research Council of Canada (NSERC) through a Discovery Grant, the Canadian Space Agency through the co-investigator grant program, and computational resources and services provided by Compute Canada, Advanced Research Computing at the University of British Columbia, and the SciServer science platform (www.sciserver.org).

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Publication:


  1. Heyl, Jeremy, et al. 2024, Monthly Notices of the Royal Astronomical Society The detection of polarized X-ray emission from the magnetar 1E 2259+586


  2. Turolla, Roberto, et al. 2023, The Astrophysical Journal IXPE and XMM-Newton Observations of the Soft Gamma Repeater SGR 1806-20


  3. Zane, Silvia, et al. 2023, The Astrophysical Journal A Strong X-Ray Polarization Signal from the Magnetar 1RXS J170849.0-400910


  4. Taverna, Roberto, et al. 2022, Science Polarized x-rays from a magnetar



  5. Forsblom, Sofia V., et al. 2024, arXiv e-prints Probing the polarized emission from SMC X-1: the brightest X-ray pulsar observed by IXPE


  6. Poutanen, Juri, et al. 2024, arXiv e-prints Studying geometry of the ultraluminous X-ray pulsar Swift J0243.6+6124 using X-ray and optical polarimetry


  7. Heyl, Jeremy, et al. 2023, arXiv e-prints X-ray Polarization Reveals the Precessions of the Neutron Star in Hercules X-1


  8. Suleimanov, Valery F., et al. 2023, Astronomy and Astrophysics X-ray polarimetry of the accreting pulsar GX 301−2


  9. Mushtukov, A. A., et al. 2023, Monthly Notices of the Royal Astronomical Society X-ray polarimetry of X-ray pulsar X Persei: another orthogonal rotator?


  10. Ng, Mason, et al. 2023, AAS/High Energy Astrophysics Division IXPE Observations of the Pulsar 4U 1626-67


  11. Doroshenko, Victor, et al. 2023, Astronomy and Astrophysics Complex variations in X-ray polarization in the X-ray pulsar LS V +44 17/RX J0440.9+4431


  12. Tsygankov, Sergey S., et al. 2023, Astronomy and Astrophysics X-ray pulsar GRO J1008−57 as an orthogonal rotator


  13. Malacaria, Christian, et al. 2023, Astronomy and Astrophysics A polarimetrically oriented X-ray stare at the accreting pulsar EXO 2030+375


  14. Forsblom, Sofia V., et al. 2023, The Astrophysical Journal IXPE Observations of the Quintessential Wind-accreting X-Ray Pulsar Vela X-1


  15. González-Caniulef, Denis, Caiazzo, Ilaria, & Heyl, Jeremy 2023, Monthly Notices of the Royal Astronomical Society Unbinned likelihood analysis for X-ray polarization


  16. Doroshenko, Victor, et al. 2022, Nature Astronomy Determination of X-ray pulsar geometry with IXPE polarimetry



Presenters

  • Jeremy Heyl

    • University of British Columbia

Authors

  • Jeremy Heyl

    • University of British Columbia