CaltechAUTHORS
Published February 1, 2023 | Version Published
Journal Article Open

Polarization Properties of the Weakly Magnetized Neutron Star X-Ray Binary GS 1826-238 in the High Soft State

Creators

  • 1. ROR icon National Institute for Astrophysics
  • 2. ROR icon Roma Tre University
  • 3. ROR icon University of Geneva
  • 4. ROR icon University of Turku
  • 5. ROR icon Space Research Institute
  • 6. ROR icon Osservatorio Astronomico di Cagliari
  • 7. ROR icon European Space Astronomy Centre
  • 8. ROR icon University College London
  • 9. ROR icon Astronomical Observatory of Rome
  • 10. ROR icon Agenzia Spaziale Italiana
  • 11. ROR icon INFN Sezione di Pisa
  • 12. ROR icon University of Pisa
  • 13. ROR icon Marshall Space Flight Center
  • 14. ROR icon INFN Sezione di Torino
  • 15. ROR icon University of Turin
  • 16. ROR icon Arcetri Astrophysical Observatory
  • 17. ROR icon University of Florence
  • 18. ROR icon INFN Sezione di Firenze
  • 19. ROR icon INFN Sezione di Roma II
  • 20. ROR icon Stanford University
  • 21. ROR icon University of Tübingen
  • 22. ROR icon Astronomical Institute
  • 23. ROR icon RIKEN
  • 24. ROR icon California Institute of Technology
  • 25. ROR icon Yamagata University
  • 26. ROR icon Osaka University
  • 27. ROR icon University of British Columbia
  • 28. ROR icon Chuo University
  • 29. ROR icon Boston University
  • 30. ROR icon St Petersburg University
  • 31. ROR icon Washington University in St. Louis
  • 32. ROR icon Observatory of Strasbourg
  • 33. ROR icon Massachusetts Institute of Technology
  • 34. ROR icon Nagoya University
  • 35. ROR icon Hiroshima University
  • 36. ROR icon University of Hong Kong
  • 37. ROR icon Pennsylvania State University
  • 38. ROR icon Institut de Planétologie et d'Astrophysique de Grenoble
  • 39. ROR icon Harvard-Smithsonian Center for Astrophysics
  • 40. ROR icon Brera Astronomical Observatory
  • 41. ROR icon University of Padua
  • 42. ROR icon University of Rome Tor Vergata
  • 43. ROR icon University of Maryland, College Park
  • 44. ROR icon University of Amsterdam
  • 45. ROR icon Guangxi University

Abstract

The launch of the Imaging X-ray Polarimetry Explorer (IXPE) on 2021 December 9 has opened a new window in X-ray astronomy. We report here the results of the first IXPE observation of a weakly magnetized neutron star, GS 1826−238, performed on 2022 March 29–31 when the source was in a high soft state. An upper limit (99.73% confidence level) of 1.3% for the linear polarization degree is obtained over the IXPE 2–8 keV energy range. Coordinated INTEGRAL and NICER observations were carried out simultaneously with IXPE. The spectral parameters obtained from the fits to the broadband spectrum were used as inputs for Monte Carlo simulations considering different possible geometries of the X-ray emitting region. Comparing the IXPE upper limit with these simulations, we can put constraints on the geometry and inclination angle of GS 1826–238.

Additional Information

© 2023. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. 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-OHBI-2017-12-I.0, agreements ASI-INAF-2017-12-H0 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). This work made use of the MAXI light curves, publicly available at http://maxi.riken.jp/top/slist.html. INTEGRAL is an ESA project with instruments and a science data center funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, and Spain) and with the participation of Russia and the USA. We thank Keith Gendreau, Craig Markwardt, and the NICER SOC for granting and performing the NICER observations of the source and helping with data reduction. J.P. and S.S.T. acknowledge support from Russian Science Foundation grant 20-12-00364 and Academy of Finland travel grants 349144, 349373, and 349906. J.P. and J.J.E.K. were supported by Academy of Finland grant 333112. Facilities: IXPE - , Swift (XRT and UVOT) - , INTEGRAL. - Software: Stingray (Huppenkothen et al. 2019a, 2019b), xspec (Arnaud 1996), ixpeobssim (Baldini et al. 2022), monk (Zhang et al. 2019).

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Published - Capitanio_2023_ApJ_943_129.pdf

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Additional details

Identifiers

Eprint ID
119423
Resolver ID
CaltechAUTHORS:20230221-19480300.56

Funding

NASA
NNM15AA18C
Agenzia Spaziale Italiana (ASI)
ASI-OHBI-2017-12-I.0
Istituto Nazionale di Astrofisica (INAF)
Agenzia Spaziale Italiana (ASI)
ASI-INAF-2017-12-H0
Agenzia Spaziale Italiana (ASI)
ASI-INFN-2017.13-H0
Agenzia Spaziale Italiana (ASI)
ASI-INAF-2022-14-HH.0
Agenzia Spaziale Italiana (ASI)
ASI-INFN 2021-43-HH.0
Istituto Nazionale di Fisica Nucleare (INFN)
Russian Science Foundation
20-12-00364
Academy of Finland
349144
Academy of Finland
349373
Academy of Finland
349906
Academy of Finland
333112

Dates

Created
2023-04-25
Created from EPrint's datestamp field
Updated
2023-04-25
Created from EPrint's last_modified field

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Caltech groups
Space Radiation Laboratory