X-Ray Polarization of the High-synchrotron-peak BL Lacertae Object 1ES 1959+650 during Intermediate and High X-Ray Flux States
: Pacciani, L.; Kim, D.E.; Middei, R.; Marshall, H.L.; Marscher, A.P.; Liodakis, I.; Agudo, I.; Jorstad, S.G.; Poutanen, J.; Errando, M.; Di Gesu, L.; Negro, M.; Tavecchio, F.; Wu, K.; Chen, C.T.; Muleri, F.; Antonelli, L.A.; Donnarumma, I.; Ehlert, S.R.; Massaro, F.; O’Dell, S.L.; Perri, M.; Puccetti, S.; Aceituno, F.J.; Bonnoli, G.; Casanova, V.; Escudero, J.; Agís-González, B.; Husillos, C.; Morcuende, D.; Otero-Santos, J.; Sota, A.; Kouch, P.M.; Lindfors, E.; Borman, G.A.; Gómez, J.L.; Kopatskaya, E.N.; Larionova, E.G.; Morozova, D.A.; Savchenko, S.S.; Vasilyev, A.A.; Zhovtan, A.V.; Blinov, D.; Gourni, A.; Kiehlmann, S.; Kourtidis, A.; Mandarakas, N.; Palaiologou, E.; Triantafyllou, N.; Vervelaki, A.; Myserlis, I.; Gurwell, M.; Keating, G.; Rao, R.; Angelakis, E.; Kraus, A.; Bachetti, M.; Baldini, L.; Baumgartner, W.H.; Bellazzini, R.; Bianchi, S.; Bongiorno, S.D.; Bonino, R.; Brez, A.; Bucciantini, N.; Capitanio, F.; Castellano, S.; Cavazzuti, E.; Ciprini, S.; Costa, E.; De Rosa, A.; Del Monte, E.; Di Lalla, N.; Di Marco, A.; Doroshenko, V.; Dovčiak, M.; Enoto, T.; Evangelista, Y.; Fabiani, S.; Ferrazzoli, R.; Garcia, J.A.; Gunji, S.; Hayashida, K.; Heyl, J.; Iwakiri, W.; Kaaret, P.; Karas, V.; Kislat, F.; Kitaguchi, T.; Kolodziejczak, J.J.; Krawczynski, H.; La Monaca, F.; Latronico, L.; Maldera, S.; Manfreda, A.; Marin, F.; Marinucci, A.; Matt, G.; Mitsuishi, I.; Mizuno, T.; Ng, C.Y.; Omodei, N.; Oppedisano, C.; Papitto, A.; Pavlov, G.G.; Peirson, A.L.; Pesce-Rollins, M.; Petrucci, P.O.; Pilia, M.; Possenti, A.; Ramsey, B.D.; Rankin, J.; Ratheesh, A.; Roberts, O.J.; Romani, R.W.; Sgró, C.; Slane, P.; Soffitta, P.; Spandre, G.; Swartz, D.A.; Tamagawa, T.; Taverna, R.; Tawara, Y.; Tennant, A.F.; Thomas, N.E.; Tombesi, F.; Trois, A.; Tsygankov, S.S.; Turolla, R.; Vink, J.; Weisskopf, M.C.; Xie, F.; Zane, S.
Publisher: American Astronomical Society
: 2025
: Astrophysical Journal
: Astrophysical Journal
: 78
: 983
: 1
: 0004-637X
: 1538-4357
DOI: https://doi.org/10.3847/1538-4357/adbbe2
: https://iopscience.iop.org/article/10.3847/1538-4357/adbbe2
: https://research.utu.fi/converis/portal/detail/Publication/491748506
We report the Imaging X-ray Polarimetry Explorer (IXPE) polarimetric and simultaneous multiwavelength observations of the high-energy-peaked BL Lacertae object (HBL) 1ES 1959+650, performed in 2022 October and 2023 August. In 2022 October, IXPE measured an average polarization degree ΠX = 9.4% ± 1.6% and an electric-vector position angle ψX = 53° ± 5°. The polarized X-ray emission can be decomposed into a constant component, plus a rotating component, with the rotation velocity ωEVPA = (−117 ± 12) deg day−1. In 2023 August, during a period of pronounced activity of the source, IXPE measured an average ΠX = 12.4% ± 0.7% and ψX = 20° ± 2°, with evidence (∼0.4% chance probability) for a rapidly rotating component with ωEVPA = 1864 ± 34 deg day−1. These findings suggest the presence of a helical magnetic field in the jet of 1ES 1959+650 or stochastic processes governing the field in turbulent plasma. Our multiwavelength campaigns from radio to X-ray reveal variability in both polarization and flux from optical to X-rays. We interpret the results in terms of a relatively slowly varying component dominating the radio and optical emission, while rapidly variable polarized components dominate the X-ray and provide minor contribution at optical wavelengths. The radio and optical data indicate that on parsec scales the magnetic field is primarily orthogonal to the jet direction. On the contrary, X-ray measurements show a magnetic field almost aligned with the parsec jet direction. Confronting with other IXPE observations, we guess that the magnetic field of HBLs on subparsec scale should be rather unstable, often changing its direction with respect to the Very Long Baseline Array jet.
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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 (now, BAE Systems). The Italian contribution is supported by the Italian Space Agency (Agenzia Spaziale Italiana, ASI) through contract 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). Funding for this work was provided in part by contract 80MSFC17C0012 from the MSFC to MIT in support of the IXPE project. Support for this work was provided in part by NASA through the Smithsonian Astrophysical Observatory (SAO) contract SV3-73016 to MIT for support of the Chandra X-Ray Center (CXC), which is operated by SAO for and on behalf of NASA under contract NAS8-03060. The IAA-CSIC co-authors acknowledge financial support from the Spanish "Ministerio de Ciencia e Innovación" (MCIN/AEI/ 10.13039/501100011033) through the Center of Excellence Severo Ochoa award for the Instituto de Astrofìisica de Andalucìa-CSIC (CEX2021-001131-S), and through grants PID2019-107847RB-C44 and PID2022-139117NB-C44. Some of the data are based on observations collected at the Observatorio de Sierra Nevada, owned and operated by the Instituto de Astrofìsica de Andalucìa (IAA-CSIC). Further data are based on observations collected at the Centro Astronómico Hispano-Alemán (CAHA), operated jointly by Junta de Andalucìa and Consejo Superior de Investigaciones Cientìficas (IAA-CSIC). The Submillimetre Array is a joint project between the SAO and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. Maunakea, the location of the SMA, is a culturally important site for the indigenous Hawaiian people; we are privileged to study the cosmos from its summit.
The data in this study include observations made with the Nordic Optical Telescope, owned in collaboration by the University of Turku and Aarhus University, and operated jointly by Aarhus University, the University of Turku, and the University of Oslo, representing Denmark, Finland and Norway, the University of Iceland, and Stockholm University at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. The data presented here were obtained in part with ALFOSC, which is provided by the Instituto de Astrofìsica de Andalucìa (IAA) under a joint agreement with the University of Copenhagen and NOT. E.L. was supported by Academy of Finland projects 317636 and 320045. We acknowledge funding to support our NOT observations from the Finnish Center for Astronomy with ESO (FINCA), University of Turku, Finland (Academy of Finland grant No. 306531). The research at Boston University was supported in part by National Science Foundation grant AST-2108622, NASA NuSTAR Guest Investigator subcontract through JPL (RSA no. 1691953), NASA Fermi Guest Investigator grants 80NSSC23K1507 and 80NSSC23K1508, and NASA Swift Guest Investigator grant 80NSSC22K0537. This study used observations conducted with the 1.8 m Perkins Telescope Observatory (PTO) in AZ (USA), which is owned and operated by Boston University. The above study is based in part on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. This research has made use of data from the RoboPol program, a collaboration between Caltech, the University of Crete, IA-FORTH, IUCAA, the MPIfR, and the Nicolaus Copernicus University, which was conducted at Skinakas Observatory in Crete, Greece. I.L. was supported by the NASA Postdoctoral Program at the Marshall Space Flight Center, administered by Oak Ridge Associated Universities under contract with NASA. Partly based on observations with the 100 m telescope of the MPIfR (Max-Planck-Institut für Radioastronomie) at Effelsberg. Observations with the 100 m radio telescope at Effelsberg have received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No. 101004719 (ORP). The Very Long Baseline Array is an instrument of the National Radio Astronomy Observatory. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated by Associated Universities, Inc.
