Polarized x-rays from a magnetar Taverna, Roberto Turolla, Roberto Muleri, Fabio Heyl, Jeremy Zane, Silvia Baldini, Luca González-Caniulef, Denis Bachetti, Matteo Rankin, John Caiazzo, Ilaria ; https://orcid.org/0000-0002-4770-5388 Di Lalla, Niccolò Doroshenko, Victor Errando, Manel Gau, Ephraim Kırmızıbayrak, Demet Krawczynski, Henric Negro, Michela Ng, Mason Omodei, Nicola Possenti, Andrea Tamagawa, Toru Uchiyama, Keisuke Weisskopf, Martin C. Agudo, Ivan Antonelli, Lucio A. Baumgartner, Wayne H. Bellazzini, Ronaldo Bianchi, Stefano Bongiorno, Stephen D. Bonino, Raffaella Brez, Alessandro Bucciantini, Niccolò Capitanio, Fiamma Castellano, Simone Cavazzuti, Elisabetta Ciprini, Stefano Costa, Enrico De Rosa, Alessandra Del Monte, Ettore Di Gesu, Laura Di Marco, Alessandro Donnarumma, Immacolata Dovčiak, Michal Ehlert, Steven R. Enoto, Teruaki Evangelista, Yuri Fabiani, Sergio Ferrazzoli, Riccardo Garcia, Javier A. Gunji, Shuichi Hayashida, Kiyoshi Iwakiri, Wataru Jorstad, Svetlana G. Karas, Vladimir Kitaguchi, Takao Kolodziejczak, Jeffery J. La Monaca, Fabio Latronico, Luca Liodakis, Ioannis Maldera, Simone Manfreda, Alberto Marin, Frédéric Marinucci, Andrea Marscher, Alan P. Marshall, Herman L. Matt, Giorgio Mitsuishi, Ikuyuki Mizuno, Tsunefumi Ng, Stephen C.-Y. O’Dell, Stephen L. Oppedisano, Chiara Papitto, Alessandro Pavlov, George G. Peirson, Abel L. Perri, Matteo Pesce-Rollins, Melissa Pilia, Maura Poutanen, Juri Puccetti, Simonetta Ramsey, Brian D. Ratheesh, Ajay Romani, Roger W. Sgrò, Carmelo Slane, Patrick Soffitta, Paolo Spandre, Gloria Tavecchio, Fabrizio Tawara, Yuzuru Tennant, Allyn F. Thomas, Nicholas E. Tombesi, Francesco Trois, Alessio Tsygankov, Sergey S. Vink, Jacco Wu, Kinwah Xie, Fei Multidisciplinary Magnetars are neutron stars with ultrastrong magnetic fields, which can be observed in x-rays. Polarization measurements could provide information on their magnetic fields and surface properties. We observed polarized x-rays from the magnetar 4U 0142+61 using the Imaging X-ray Polarimetry Explorer and found a linear polarization degree of 13.5 ± 0.8% averaged over the 2– to 8–kilo–electron volt band. The polarization changes with energy: The degree is 15.0 ± 1.0% at 2 to 4 kilo–electron volts, drops below the instrumental sensitivity ~4 to 5 kilo–electron volts, and rises to 35.2 ± 7.1% at 5.5 to 8 kilo–electron volts. The polarization angle also changes by 90° at ~4 to 5 kilo–electron volts. These results are consistent with a model in which thermal radiation from the magnetar surface is reprocessed by scattering off charged particles in the magnetosphere. American Association for the Advancement of Science 2022 info:eu-repo/semantics/article doc-type:article text http://purl.org/coar/resource_type/c_2df8fbb1 https://research-explorer.ista.ac.at/record/15205 Taverna R, Turolla R, Muleri F, et al. Polarized x-rays from a magnetar. <i>Science</i>. 2022;378(6620):646-650. doi:<a href="https://doi.org/10.1126/science.add0080">10.1126/science.add0080</a> eng info:eu-repo/semantics/altIdentifier/doi/10.1126/science.add0080 info:eu-repo/semantics/altIdentifier/issn/0036-8075 info:eu-repo/semantics/altIdentifier/e-issn/1095-9203 info:eu-repo/semantics/altIdentifier/arxiv/2205.08898 info:eu-repo/semantics/openAccess