Polarization Properties of the Weakly Magnetized Neutron Star X-Ray Binary GS 1826-238 in the High Soft State
: Capitanio Fiamma, Fabiani Sergio, Gnarini Andrea, Ursini Francesco, Ferrigno Carlo, Matt Giorgio, Poutanen Juri, Cocchi Massimo, Mikusincova Romana, Farinelli Ruben, Bianchi Stefano, Kajava Jari J. E., Muleri Fabio, Sanchez-Fernandez Celia, Soffitta Paolo, Wu Kinwah, Agudo Iván, Antonelli Lucio A., Bachetti Matteo, Baldini Luca, Baumgartner Wayne H., Bellazzini Ronaldo, Bongiorno Stephen D., Bonino Raffaella, Brez Alessandro, Bucciantini Niccolò, Castellano Simone, Cavazzuti Elisabetta, Ciprini Stefano, Costa Enrico, De Rosa Alessandra, Del Monte Ettore, Di Gesu Laura, Di Lalla Niccolò, Di Marco Alessandro, Donnarumma Immacolata, Doroshenko Victor, Dovčiak Michal, Ehlert Steven R., Enoto Teruaki, Evangelista Yuri, Ferrazzoli Riccardo, Garcia Javier A., Gunji Shuichi, Hayashida Kiyoshi, Heyl Jeremy, Iwakiri Wataru, Jorstad Svetlana G., Karas Vladimir, Kitaguchi Takao, Kolodziejczak Jeffery J., Krawczynski Henric, La Monaca Fabio, Latronico Luca, Liodakis Ioannis, Maldera Simone, Manfreda Alberto, Marin Frédéric, Marinucci Andrea, Marscher Alan P., Marshall Herman L., Mitsuishi Ikuyuki, Mizuno Tsunefumi, Ng C.-Y., O'Dell Stephen L., Omodei Nicola, Oppedisano Chiara, Papitto Alessandro, Pavlov George G., Peirson Abel L., Perri Matteo, Pesce-Rollins Melissa, Petrucci Pierre-Olivier, Pilia Maura, Possenti Andrea, Puccetti Simonetta, Ramsey Brian D., Rankin John, Ratheesh Ajay, Romani Roger W., Sgrò Carmelo, Slane Patrick, Spandre Gloria, Tamagawa Toru, Tavecchio Fabrizio, Taverna Roberto, Tawara Yuzuru, Tennant Allyn F., Thomas Nicholas E., Tombesi Francesco, Trois Alessio, Tsygankov Sergey S., Turolla Roberto, Vink Jacco, Weisskopf Martin C., Xie Fei, Zane Silvia
Publisher: IOP Publishing Ltd
: 2023
: Astrophysical Journal
: ASTROPHYSICAL JOURNAL
: ASTROPHYS J
: 129
: 943
: 2
: 10
: 0004-637X
: 1538-4357
DOI: https://doi.org/10.3847/1538-4357/acae88
: https://iopscience.iop.org/article/10.3847/1538-4357/acae88
: https://research.utu.fi/converis/portal/detail/Publication/178965999
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.
