Polarized x-rays from a magnetar
- Creators
- Taverna, Roberto
- Turolla, Roberto
- Muleri, Fabio
- Heyl, Jeremy
- Zane, Silvia
- Baldini, Luca
- González-Caniulef, Denis
- Bachetti, Matteo
- Rankin, John
- Caiazzo, Ilaria
- 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
Abstract
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.
Copyright and License
© 2022 the authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original US government works. https://www.science.org/about/science-licenses-journal-article-reuse
Acknowledgement
We thank three anonymous referees for helpful and constructive comments that improved the paper. This paper is based on observations made by the IXPE, a joint US and Italian mission. The US contribution to the IXPE mission is supported by NASA and led and managed by the MSFC with industry partner Ball Aerospace (contract NNM15AA18C). The Italian contribution is supported by ASI through contract ASI-OHBI-2017-12-I.0, agreements ASI-INAF-2017-12-H0 and ASI-INFN-2017.13-H0 and the SSDC with agreements ASI-INAF-2022-14-HH.0 and ASI-INFN 2021-43-HH.0, and by INAF and INFN. Data products were 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 GSFC.
Funding
R.Ta. and R.Tu. acknowledge financial support from the Italian MUR through grant PRIN 2017LJ39LM. J.H., D.G.-C., I.C., and D.K. acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC), funding reference number 5007110, and the Canadian Space Agency. D.G.-C. is a Canadian Institute for Theoretical Astrophysical (CITA) National Fellow (grant no. CITA 490888-16). E.G. and H.K. acknowledge NASA support under grants 80NSSC18K0264, 80NSSC22K1291, 80NSSC21K1817, and NNX16AC24G. M.Ne. acknowledges support from NASA under award 80GSFC21M0002. T.T. was supported by grant JSPS KAKENHI JP19H05609. F.Mu., J.R., S.B., E.Co., E.D.M., A.D.M., Y.E., S.F., R.F., F.L.M., G.M., M.Pe., A.R., P.So., and A.T. were supported by ASI and INAF under grants ASI-INAF-2017-12-H0 and ASI-INAF-2022-14-HH.0. L.B., L.L., R.Be., R.Bo., A.B., S.Ca., S.M., A.Mar., C.O., M.P.-R., C.S., and G.S. were supported by ASI and INFN under grants ASI-INFN-2017.13-H0 and ASI-INFN-2021-43-HH.0.
Contributions
R.Ta., R.Tu., F.Mu., J.H., S.Z., L.B., J.R., and M.C.W. planned the observing campaign. R.Ta., R.Tu., F.Mu., J.H., S.Z., L.B., J.R., D.G.-C., M.B., I.C., N.D.L., E.G., D.K., H.K., M.Ne., M. Ng, N.O., A.Po., T.T., and K.U. analyzed the data. R.Ta., R.Tu., F.Mu., J.H., S.Z., L.B., J.R., D.G.-C., M.B., I.C., A.Po., T.T., and K.U. modeled the data. R.Ta., R.Tu., F.Mu., J.H., S.Z., L.B., J.R., D.G.-C., M.B., and A.Po. wrote the manuscript. V.D. and M.E. served as internal reviewers. All the other authors contributed to the design and science case of the IXPE mission and to the planning of the observations in this paper. All authors provided input and comments on the manuscript.
Data Availability
The IXPE observation of 4U 0142+61 is available in the HEASARC IXPE Data Archive https://heasarc.gsfc.nasa.gov/docs/ixpe/archive/ under ObsID 01003299. The IXPE software is available at https://github.com/lucabaldini/ixpeobssim and documented at https://ixpeobssim.readthedocs.io. Our measured polarizations are listed in table S2, and the results of our model fitting are listed in tables S1 and S3.
Conflict of Interest
The authors declare there are no competing interests.
Code Availability
The code used for the equatorial belt simulation is available at https://github.com/robertotaverna/magMC and archived on Zenodo (31).
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Additional details
- ISSN
- 1095-9203
- Natural Sciences and Engineering Research Council
- 5007110
- Canadian Space Agency
- Canadian Institute for Theoretical Astrophysics
- 490888-16
- National Aeronautics and Space Administration
- 80NSSC18K0264
- National Aeronautics and Space Administration
- 80NSSC22K1291
- National Aeronautics and Space Administration
- 80NSSC21K1817
- National Aeronautics and Space Administration
- NNX16AC24G
- National Aeronautics and Space Administration
- 80GSFC21M0002
- Japan Society for the Promotion of Science
- JP19H05609
- Agenzia Spaziale Italiana
- ASI-INAF-2017-12-H0
- Agenzia Spaziale Italiana
- ASI-INAF-2022-14-HH.0
- Agenzia Spaziale Italiana
- ASI-INFN-2017.13-H0
- Agenzia Spaziale Italiana
- ASI-INFN-2021-43-HH.0
- Caltech groups
- Space Radiation Laboratory, TAPIR