Detection of X-Ray Polarization from the Blazar 1ES 1959+650 with the Imaging X-Ray Polarimetry Explorer
Authors: Errando Manel , Liodakis Ioannis , Marscher Alan P. , Marshall Herman L. , Middei Riccardo , Negro Michela , Peirson Abel Lawrence , Perri Matteo , Puccetti Simonetta , Rabinowitz Pazit L. , Agudo Iván , Jorstad Svetlana G. , Savchenko Sergey S. , Blinov Dmitry , Bourbah Ioakeim G. , Kiehlmann Sebastian , Kontopodis Evangelos , Mandarakas Nikos , Romanopoulos Stylianos , Skalidis Raphael , Vervelaki Anna , Aceituno Francisco José , Bernardos Maria I. , Bonnoli Giacomo , Casanova Víctor , Agís-González Beatriz , Husillos César , Marchini Alessandro , Sota Alfredo , Kouch Pouya M. , Lindfors Elina , Casadio Carolina , Escudero Juan , Myserlis Ioannis , Imazawa Ryo , Sasada Mahito , Fukazawa Yasushi , Kawabata Koji S. , Uemura Makoto , Mizuno Tsunefumi , Nakaoka Tatsuya , Akitaya Hiroshi , Gurwell Mark , Keating Garrett K. , Rao Ramprasad , Ingram Adam , Massaro Francesco , Antonelli Lucio Angelo , Bonino Raffaella , Cavazzuti Elisabetta , Chen Chien-Ting , Cibrario Nicolò , Ciprini Stefano , De Rosa Alessandra , Di Gesu Laura , Di Pierro Federico , Donnarumma Immacolata , Ehlert Steven R. , Fenu Francesco , Gau Ephraim , Karas Vladimir , Kim Dawoon E. , Krawczynski Henric , Laurenti Marco , Lisalda Lindsey , López-Coto Rubén , Madejski Grzegorz , Marin Frédéric , Marinucci Andrea , Mitsuishi Ikuyuki , Muleri Fabio , Pacciani Luigi , Paggi Alessandro , Petrucci Pierre-Olivier , Rodriguez Cavero Nicole , Romani Roger W. , Tavecchio Fabrizio , Tugliani Stefano , Wu Kinwah , Bachetti Matteo , Baldini Luca , Baumgartner Wayne H. , Bellazzini Ronaldo , Bianchi Stefano , Bongiorno Stephen D. , Brez Alessandro , Bucciantini Niccolò , Capitanio Fiamma , Castellano Simone , Costa Enrico , Del Monte Ettore , Di Lalla Niccolò , Di Marco Alessandro , Doroshenko Victor , Dovčiak Michal , Enoto Teruaki , Evangelista Yuri , Fabiani Sergio , Ferrazzoli Riccardo , Garcia Javier A. , Gunji Shuichi , Hayashida Kiyoshi , Heyl Jeremy , Iwakiri Wataru , Kaaret Philip , Kislat Fabian , Kitaguchi Takao , Kolodziejczak Jeffery J. , La Monaca Fabio , Latronico Luca , Maldera Simone , Manfreda Alberto , Matt Giorgio , Ng C.-Y. , O’Dell Stephen L. , Omodei Nicola , Oppedisano Chiara , Papitto Alessandro , Pavlov George G. , Pesce-Rollins Melissa , Pilia Maura , Possenti Andrea , Poutanen Juri , Ramsey Brian D. , Rankin John , Ratheesh Ajay , Roberts Oliver J. , Sgrò Carmelo , Slane Patrick , Soffitta Paolo , Spandre Gloria , Swartz Douglas A. , Tamagawa Toru , 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 
Published: February 2024

Abstract
Observations of linear polarization in the 2–8 keV energy range with the Imaging X-ray Polarimetry Explorer (IXPE) explore the magnetic field geometry and dynamics of the regions generating nonthermal radiation in relativistic jets of blazars. These jets, particularly in blazars whose spectral energy distribution peaks at X-ray energies, emit X-rays via synchrotron radiation from high-energy particles within the jet. IXPE observations of the X-ray-selected BL Lac–type blazar 1ES 1959+650 on 2022 May 3–4 showed a significant linear polarization degree of Πx = 8.0% ± 2.3% at an electric-vector position angle ψ
x = 123° ± 8°. However, on 2022 June 9–12, only an upper limit of Πx ≤ 5.1% could be derived (at the 99% confidence level). The degree of optical polarization at that time, ΠO ∼ 5%, is comparable to the X-ray measurement. We investigate possible scenarios for these findings, including temporal and geometrical depolarization effects. Unlike some other X-ray-selected BL Lac objects, there is no significant chromatic dependence of the measured polarization in 1ES 1959+650, and its low X-ray polarization may be attributed to turbulence in the jet flow with dynamical timescales shorter than 1 day.