eprintid: 10160826 rev_number: 6 eprint_status: archive userid: 699 dir: disk0/10/16/08/26 datestamp: 2022-11-28 16:03:08 lastmod: 2022-11-28 16:03:08 status_changed: 2022-11-28 16:03:08 type: article metadata_visibility: show sword_depositor: 699 creators_name: Liodakis, Ioannis creators_name: Marscher, Alan P creators_name: Agudo, Iván creators_name: Berdyugin, Andrei V creators_name: Bernardos, Maria I creators_name: Bonnoli, Giacomo creators_name: Borman, George A creators_name: Casadio, Carolina creators_name: Casanova, Vı Ctor creators_name: Cavazzuti, Elisabetta creators_name: Rodriguez Cavero, Nicole creators_name: Di Gesu, Laura creators_name: Di Lalla, Niccoló creators_name: Donnarumma, Immacolata creators_name: Ehlert, Steven R creators_name: Errando, Manel creators_name: Escudero, Juan creators_name: Garcı A-Comas, Maya creators_name: Agı S-González, Beatriz creators_name: Husillos, César creators_name: Jormanainen, Jenni creators_name: Jorstad, Svetlana G creators_name: Kagitani, Masato creators_name: Kopatskaya, Evgenia N creators_name: Kravtsov, Vadim creators_name: Krawczynski, Henric creators_name: Lindfors, Elina creators_name: Larionova, Elena G creators_name: Madejski, Grzegorz M creators_name: Marin, Frédéric creators_name: Marchini, Alessandro creators_name: Marshall, Herman L creators_name: Morozova, Daria A creators_name: Massaro, Francesco creators_name: Masiero, Joseph R creators_name: Mawet, Dimitri creators_name: Middei, Riccardo creators_name: Millar-Blanchaer, Maxwell A creators_name: Myserlis, Ioannis creators_name: Negro, Michela creators_name: Nilsson, Kari creators_name: O'Dell, Stephen L creators_name: Omodei, Nicola creators_name: Pacciani, Luigi creators_name: Paggi, Alessandro creators_name: Panopoulou, Georgia V creators_name: Peirson, Abel L creators_name: Perri, Matteo creators_name: Petrucci, Pierre-Olivier creators_name: Poutanen, Juri creators_name: Puccetti, Simonetta creators_name: Romani, Roger W creators_name: Sakanoi, Takeshi creators_name: Savchenko, Sergey S creators_name: Sota, Alfredo creators_name: Tavecchio, Fabrizio creators_name: Tinyanont, Samaporn creators_name: Vasilyev, Andrey A creators_name: Weaver, Zachary R creators_name: Zhovtan, Alexey V creators_name: Antonelli, Lucio A creators_name: Bachetti, Matteo creators_name: Baldini, Luca creators_name: Baumgartner, Wayne H creators_name: Bellazzini, Ronaldo creators_name: Bianchi, Stefano creators_name: Bongiorno, Stephen D creators_name: Bonino, Raffaella creators_name: Brez, Alessandro creators_name: Bucciantini, Niccoló creators_name: Capitanio, Fiamma creators_name: Castellano, Simone creators_name: Ciprini, Stefano creators_name: Costa, Enrico creators_name: De Rosa, Alessandra creators_name: Del Monte, Ettore creators_name: Di Marco, Alessandro creators_name: Doroshenko, Victor creators_name: Dovčiak, Michal creators_name: Enoto, Teruaki creators_name: Evangelista, Yuri creators_name: Fabiani, Sergio creators_name: Ferrazzoli, Riccardo creators_name: Garcia, Javier A creators_name: Gunji, Shuichi creators_name: Hayashida, Kiyoshi creators_name: Heyl, Jeremy creators_name: Iwakiri, Wataru creators_name: Karas, Vladimir creators_name: Kitaguchi, Takao creators_name: Kolodziejczak, Jeffery J creators_name: La Monaca, Fabio creators_name: Latronico, Luca creators_name: Maldera, Simone creators_name: Manfreda, Alberto creators_name: Marinucci, Andrea creators_name: Matt, Giorgio creators_name: Mitsuishi, Ikuyuki creators_name: Mizuno, Tsunefumi creators_name: Muleri, Fabio creators_name: Ng, Stephen C-Y creators_name: Oppedisano, Chiara creators_name: Papitto, Alessandro creators_name: Pavlov, George G creators_name: Pesce-Rollins, Melissa creators_name: Pilia, Maura creators_name: Possenti, Andrea creators_name: Ramsey, Brian D creators_name: Rankin, John creators_name: Ratheesh, Ajay creators_name: Sgró, Carmelo creators_name: Slane, Patrick creators_name: Soffitta, Paolo creators_name: Spandre, Gloria creators_name: Tamagawa, Toru creators_name: Taverna, Roberto creators_name: Tawara, Yuzuru creators_name: Tennant, Allyn F creators_name: Thomas, Nicolas E creators_name: Tombesi, Francesco creators_name: Trois, Alessio creators_name: Tsygankov, Sergey creators_name: Turolla, Roberto creators_name: Vink, Jacco creators_name: Weisskopf, Martin C creators_name: Wu, Kinwah creators_name: Xie, Fei creators_name: Zane, Silvia title: Polarized blazar X-rays imply particle acceleration in shocks ispublished: pub divisions: UCL divisions: B04 divisions: C06 divisions: F63 keywords: X-Rays, Radiography, Acceleration, Aircraft, Cell Nucleus note: Open Access: This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. abstract: Most of the light from blazars, active galactic nuclei with jets of magnetized plasma that point nearly along the line of sight, is produced by high-energy particles, up to around 1 TeV. Although the jets are known to be ultimately powered by a supermassive black hole, how the particles are accelerated to such high energies has been an unanswered question. The process must be related to the magnetic field, which can be probed by observations of the polarization of light from the jets. Measurements of the radio to optical polarization-the only range available until now-probe extended regions of the jet containing particles that left the acceleration site days to years earlier1-3, and hence do not directly explore the acceleration mechanism, as could X-ray measurements. Here we report the detection of X-ray polarization from the blazar Markarian 501 (Mrk 501). We measure an X-ray linear polarization degree ΠX of around 10%, which is a factor of around 2 higher than the value at optical wavelengths, with a polarization angle parallel to the radio jet. This points to a shock front as the source of particle acceleration and also implies that the plasma becomes increasingly turbulent with distance from the shock. date: 2022-11-24 date_type: published publisher: Springer Science and Business Media LLC official_url: https://doi.org/10.1038/s41586-022-05338-0 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green article_type_text: Journal Article verified: verified_manual elements_id: 1976677 doi: 10.1038/s41586-022-05338-0 medium: Print-Electronic pii: 10.1038/s41586-022-05338-0 lyricists_name: Zane, Silvia lyricists_name: Wu, Kinwah lyricists_id: SZANE58 lyricists_id: KWUXX50 actors_name: Wu, Kinwah actors_name: Flynn, Bernadette actors_id: KWUXX50 actors_id: BFFLY94 actors_role: owner actors_role: impersonator full_text_status: public publication: Nature volume: 611 number: 7937 pagerange: 677-681 event_location: England issn: 0028-0836 citation: Liodakis, Ioannis; Marscher, Alan P; Agudo, Iván; Berdyugin, Andrei V; Bernardos, Maria I; Bonnoli, Giacomo; Borman, George A; ... Zane, Silvia; + view all <#> Liodakis, Ioannis; Marscher, Alan P; Agudo, Iván; Berdyugin, Andrei V; Bernardos, Maria I; Bonnoli, Giacomo; Borman, George A; Casadio, Carolina; Casanova, Vı Ctor; Cavazzuti, Elisabetta; Rodriguez Cavero, Nicole; Di Gesu, Laura; Di Lalla, Niccoló; Donnarumma, Immacolata; Ehlert, Steven R; Errando, Manel; Escudero, Juan; Garcı A-Comas, Maya; Agı S-González, Beatriz; Husillos, César; Jormanainen, Jenni; Jorstad, Svetlana G; Kagitani, Masato; Kopatskaya, Evgenia N; Kravtsov, Vadim; Krawczynski, Henric; Lindfors, Elina; Larionova, Elena G; Madejski, Grzegorz M; Marin, Frédéric; Marchini, Alessandro; Marshall, Herman L; Morozova, Daria A; Massaro, Francesco; Masiero, Joseph R; Mawet, Dimitri; Middei, Riccardo; Millar-Blanchaer, Maxwell A; Myserlis, Ioannis; Negro, Michela; Nilsson, Kari; O'Dell, Stephen L; Omodei, Nicola; Pacciani, Luigi; Paggi, Alessandro; Panopoulou, Georgia V; Peirson, Abel L; Perri, Matteo; Petrucci, Pierre-Olivier; Poutanen, Juri; Puccetti, Simonetta; Romani, Roger W; Sakanoi, Takeshi; Savchenko, Sergey S; Sota, Alfredo; Tavecchio, Fabrizio; Tinyanont, Samaporn; Vasilyev, Andrey A; Weaver, Zachary R; Zhovtan, Alexey V; Antonelli, Lucio A; Bachetti, Matteo; Baldini, Luca; Baumgartner, Wayne H; Bellazzini, Ronaldo; Bianchi, Stefano; Bongiorno, Stephen D; Bonino, Raffaella; Brez, Alessandro; Bucciantini, Niccoló; Capitanio, Fiamma; Castellano, Simone; Ciprini, Stefano; Costa, Enrico; De Rosa, Alessandra; Del Monte, Ettore; 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; Karas, Vladimir; Kitaguchi, Takao; Kolodziejczak, Jeffery J; La Monaca, Fabio; Latronico, Luca; Maldera, Simone; Manfreda, Alberto; Marinucci, Andrea; Matt, Giorgio; Mitsuishi, Ikuyuki; Mizuno, Tsunefumi; Muleri, Fabio; Ng, Stephen C-Y; Oppedisano, Chiara; Papitto, Alessandro; Pavlov, George G; Pesce-Rollins, Melissa; Pilia, Maura; Possenti, Andrea; Ramsey, Brian D; Rankin, John; Ratheesh, Ajay; Sgró, Carmelo; Slane, Patrick; Soffitta, Paolo; Spandre, Gloria; Tamagawa, Toru; Taverna, Roberto; Tawara, Yuzuru; Tennant, Allyn F; Thomas, Nicolas E; Tombesi, Francesco; Trois, Alessio; Tsygankov, Sergey; Turolla, Roberto; Vink, Jacco; Weisskopf, Martin C; Wu, Kinwah; Xie, Fei; Zane, Silvia; - view fewer <#> (2022) Polarized blazar X-rays imply particle acceleration in shocks. Nature , 611 (7937) pp. 677-681. 10.1038/s41586-022-05338-0 <https://doi.org/10.1038/s41586-022-05338-0>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10160826/1/s41586-022-05338-0.pdf