X-Ray Polarization of the High-synchrotron-peak BL Lacertae Object 1ES 1959+650 during Intermediate and High X-Ray Flux States

Abstract 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 Π X = 9.4% ± 1.6% and an electric-vector position angle ψ X = 53° ± 5°. The polarized X-ray emission can be decomposed into a constant component, plus a rotating component, with the rotation velocity ω EVPA = (−117 ± 12) deg day −1 . In 2023 August, during a period of pronounced activity of the source, IXPE measured an average Π X = 12.4% ± 0.7% and ψ X = 20° ± 2°, with evidence (∼0.4% chance probability) for a rapidly rotating component with ω EVPA = 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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Publication Details

Journal
The Astrophysical Journal
Published
2025-04-08
DOI
https://doi.org/10.3847/1538-4357/adbbe2
Citations
4
Primary Topic
Astrophysics and Cosmic Phenomena
Type
article
Field-Weighted Citation Impact
7.48

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article

X-Ray Polarization of the High-synchrotron-peak BL Lacertae Object 1ES 1959+650 during Intermediate and High X-Ray Flux States

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4 citations
The Astrophysical Journal
Astrophysics and Cosmic Phenomena
7.48
article

X-Ray Polarization of the High-synchrotron-peak BL Lacertae Object 1ES 1959+650 during Intermediate and High X-Ray Flux States

E. V. Palaiologou, Niccolò Di Lalla, Fabian Kislat, F. Massaro, Jeffery J. Kolodziejczak, Juri Poutanen, R. Bonino, A. Brez, Laura Di Gesu, Simonetta Puccetti, Michal Dovčiak, Y. Evangelista, S. Ciprini, Dawoon E. Kim, A. A. Vasilyev, Silvia Zane, M. Pilia, Allyn F. Tennant, Jeremy Heyl, Daniel Morcuende, Andrea Possenti, Victor Doroshenko, Chien‐Ting Chen, C. Husillos, Jacco Vink, A. Sota, Herman L. Marshall, A. Kraus, Ioannis Liodakis, А. В. Жовтан, Pouya M. Kouch, E. Costa, Garrett K. Keating, F. Tavecchio, E. Angelakis, G. Matt, Javier A. García, Pierre-Olivier Petrucci, Svetlana G. Jorstad, Alessandro Di Marco, P. Soffitta, Alberto Manfreda, W. H. Baumgartner, Alessandra De Rosa, D. Blinov, Jorge Otero-Santos, Kinwah Wu, M. Perri, Martin C. Weisskopf, Beatriz Agı́s-González, Е. Г. Ларионова, E. Del Monte, G. Spandre, O. J. Roberts, I. Myserlis, Fei Xie, George G. Pavlov, Roger W. Romani, I. Agudo, Francesco Tombesi, Ramprasad Rao, M. Pesce-Rollins, Frédéric Marin, Patrick Slane, Toru Tamagawa, S. Kiehlmann, Yuzuru Tawara, Fiamma Capitanio, Steven R. Ehlert, Stephen L. O’Dell, Stephen D. Bongiorno, S. Maldera, C. Sgrò, V. Karas, John Rankin, Alessandro Papitto, F. J. Aceituno, A. Trois, Sergey S. Tsygankov, E. N. Kopatskaya, Riccardo Ferrazzoli, W. Iwakiri, Fabio Muleri, N. Mandarakas, G. Bonnoli, Brian D. Ramsey, E. Lindfors, V. Casanova, Tsunefumi Mizuno, Ikuyuki Mitsuishi, Roberto Taverna, Teruaki Enoto, R. Bellazzini, Г. А. Борман, С. С. Савченко, E. Cavazzuti, Sergio Fabiani, Douglas A. Swartz, H. Krawczynski, Shuichi Gunji, Michela Negro, Andrea Marinucci, R. Middei, Daria A. Morozova, Mark Gurwell, L. Pacciani, Alan P. Marscher, Abel L. Peirson, Matteo Bachetti, C. Oppedisano, Nikolaos Triantafyllou, Simone Castellano, P. Kaaret, L. Baldini, Ajay Ratheesh, M. Errando, N. Bucciantini, José L. Gómez, Fabio La Monaca, L. Latronico, Nicholas E. Thomas, I. Donnarumma, L. A. Antonelli, S. Bianchi, Anna Vervelaki, Juan Escudero, Roberto Turolla, N. Omodei, C.‐Y. Ng, Kiyoshi Hayashida, Takao Kitaguchi, Anastasia Gourni, Angelos Kourtidis
article en
4 citations

Abstract

Abstract 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 Π X = 9.4% ± 1.6% and an electric-vector position angle ψ X = 53° ± 5°. The polarized X-ray emission can be decomposed into a constant component, plus a rotating component, with the rotation velocity ω EVPA = (−117 ± 12) deg day −1 . In 2023 August, during a period of pronounced activity of the source, IXPE measured an average Π X = 12.4% ± 0.7% and ψ X = 20° ± 2°, with evidence (∼0.4% chance probability) for a rapidly rotating component with ω EVPA = 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.

The Astrophysical JournalVol. 983(1)
National Science Foundation, Smithsonian Institution, National Aeronautics and Space Administration, Oak Ridge Associated Universities, California Institute of Technology, Aarhus Universitet, European Commission, Academia Sinica, Academy of Finland, Nuclear Safety and Security Commission, Agenzia Spaziale Italiana, University of Crete, Ministerio de Ciencia e Innovación, Istituto Nazionale di Astrofisica, Universitetet i Oslo, Háskóli Íslands, Turun Yliopisto, Stockholms Universitet, Istituto Nazionale di Fisica Nucleare, Instituto de Astrofísica de Andalucía, Marshall Space Flight Center, Goddard Space Flight Center, Smithsonian Astrophysical Observatory, Agencia Estatal de Investigación
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