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Polarized blazar X-rays imply particle acceleration in shocks

Liodakis, Ioannis and Marscher, Alan P. and Agudo, Iván and Berdyugin, Andrei V. and Bernardos, Maria I. and Bonnoli, Giacomo and Borman, George A. and Casadio, Carolina and Casanova, Vı́ctor and Cavazzuti, Elisabetta and Rodriguez Cavero, Nicole and Di Gesu, Laura and Di Lalla, Niccoló and Donnarumma, Immacolata and Ehlert, Steven R. and Errando, Manel and Escudero, Juan and Garcı́a-Comas, Maya and Agı́s-González, Beatriz and Husillos, César and Jormanainen, Jenni and Jorstad, Svetlana G. and Kagitani, Masato and Kopatskaya, Evgenia N. and Kravtsov, Vadim and Krawczynski, Henric and Lindfors, Elina and Larionova, Elena G. and Madejski, Grzegorz M. and Marin, Frédéric and Marchini, Alessandro and Marshall, Herman L. and Morozova, Daria A. and Massaro, Francesco and Masiero, Joseph R. and Mawet, Dimitri and Middei, Riccardo and Millar-Blanchaer, Maxwell A. and Myserlis, Ioannis and Negro, Michela and Nilsson, Kari and O’Dell, Stephen L. and Omodei, Nicola and Pacciani, Luigi and Paggi, Alessandro and Panopoulou, Georgia V. and Peirson, Abel L. and Perri, Matteo and Petrucci, Pierre-Olivier and Poutanen, Juri and Puccetti, Simonetta and Romani, Roger W. and Sakanoi, Takeshi and Savchenko, Sergey S. and Sota, Alfredo and Tavecchio, Fabrizio and Tinyanont, Samaporn and Vasilyev, Andrey A. and Weaver, Zachary R. and Zhovtan, Alexey V. and Antonelli, Lucio A. and Bachetti, Matteo and Baldini, Luca and Baumgartner, Wayne H. and Bellazzini, Ronaldo and Bianchi, Stefano and Bongiorno, Stephen D. and Bonino, Raffaella and Brez, Alessandro and Bucciantini, Niccolò and Capitanio, Fiamma and Castellano, Simone and Ciprini, Stefano and Costa, Enrico and De Rosa, Alessandra and Del Monte, Ettore and Di Marco, Alessandro and Doroshenko, Victor and Dovčiak, Michal and Enoto, Teruaki and Evangelista, Yuri and Fabiani, Sergio and Ferrazzoli, Riccardo and García, Javier A. and Gunji, Shuichi and Hayashida, Kiyoshi and Heyl, Jeremy and Iwakiri, Wataru and Karas, Vladimir and Kitaguchi, Takao and Kolodziejczak, Jeffery J. and La Monaca, Fabio and Latronico, Luca and Maldera, Simone and Manfreda, Alberto and Marinucci, Andrea and Matt, Giorgio and Mitsuishi, Ikuyuki and Mizuno, Tsunefumi and Muleri, Fabio and Ng, Stephen C.-Y. and Oppedisano, Chiara and Papitto, Alessandro and Pavlov, George G. and Pesce-Rollins, Melissa and Pilia, Maura and Possenti, Andrea and Ramsey, Brian D. and Rankin, John and Ratheesh, Ajay and Sgró, Carmelo and Slane, Patrick and Soffitta, Paolo and Spandre, Gloria and Tamagawa, Toru and Taverna, Roberto and Tawara, Yuzuru and Tennant, Allyn F. and Thomas, Nicolas E. and Tombesi, Francesco and Trois, Alessio and Tsygankov, Sergey and Turolla, Roberto and Vink, Jacco and Weisskopf, Martin C. and Wu, Kinwah and Xie, Fei and Zane, Silvia (2022) Polarized blazar X-rays imply particle acceleration in shocks. Nature, 611 (7937). pp. 677-681. ISSN 0028-0836. PMCID PMC9684068. doi:10.1038/s41586-022-05338-0.

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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 earlier, 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.

Item Type:Article
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URLURL TypeDescription CentralArticle
Liodakis, Ioannis0000-0001-9200-4006
Marscher, Alan P.0000-0001-7396-3332
Agudo, Iván0000-0002-3777-6182
Berdyugin, Andrei V.0000-0002-9353-5164
Bernardos, Maria I.0000-0001-8872-1168
Bonnoli, Giacomo0000-0003-2464-9077
Casadio, Carolina0000-0003-1117-2863
Cavazzuti, Elisabetta0000-0001-7150-9638
Rodriguez Cavero, Nicole0000-0001-5256-0278
Di Gesu, Laura0000-0002-5614-5028
Di Lalla, Niccoló0000-0002-7574-1298
Donnarumma, Immacolata0000-0002-4700-4549
Ehlert, Steven R.0000-0003-4420-2838
Errando, Manel0000-0002-1853-863X
Escudero, Juan0000-0002-4131-655X
Garcı́a-Comas, Maya0000-0003-2323-4486
Agı́s-González, Beatriz0000-0001-7702-8931
Husillos, César0000-0001-8286-5443
Jormanainen, Jenni0000-0003-4519-7751
Jorstad, Svetlana G.0000-0001-6158-1708
Kagitani, Masato0000-0002-4115-7122
Kopatskaya, Evgenia N.0000-0001-9518-337X
Kravtsov, Vadim0000-0002-7502-3173
Krawczynski, Henric0000-0002-1084-6507
Lindfors, Elina0000-0002-9155-6199
Larionova, Elena G.0000-0002-2471-6500
Marin, Frédéric0000-0003-4952-0835
Marchini, Alessandro0000-0003-3779-6762
Marshall, Herman L.0000-0002-6492-1293
Morozova, Daria A.0000-0002-9407-7804
Massaro, Francesco0000-0002-1704-9850
Masiero, Joseph R.0000-0003-2638-720X
Mawet, Dimitri0000-0002-8895-4735
Middei, Riccardo0000-0001-9815-9092
Millar-Blanchaer, Maxwell A.0000-0001-6205-9233
Myserlis, Ioannis0000-0003-3025-9497
Negro, Michela0000-0002-6548-5622
Nilsson, Kari0000-0002-1445-8683
O’Dell, Stephen L.0000-0002-1868-8056
Omodei, Nicola0000-0002-5448-7577
Pacciani, Luigi0000-0001-6897-5996
Paggi, Alessandro0000-0002-5646-2410
Panopoulou, Georgia V.0000-0001-7482-5759
Peirson, Abel L.0000-0001-6292-1911
Perri, Matteo0000-0003-3613-4409
Petrucci, Pierre-Olivier0000-0001-6061-3480
Poutanen, Juri0000-0002-0983-0049
Puccetti, Simonetta0000-0002-2734-7835
Romani, Roger W.0000-0001-6711-3286
Sakanoi, Takeshi0000-0002-7146-9020
Savchenko, Sergey S.0000-0003-4147-3851
Sota, Alfredo0000-0002-9404-6952
Tavecchio, Fabrizio0000-0003-0256-0995
Vasilyev, Andrey A.0000-0002-8293-0214
Weaver, Zachary R.0000-0001-6314-0690
Antonelli, Lucio A.0000-0002-5037-9034
Bachetti, Matteo0000-0002-4576-9337
Baldini, Luca0000-0002-9785-7726
Baumgartner, Wayne H.0000-0002-5106-0463
Bellazzini, Ronaldo0000-0002-2469-7063
Bianchi, Stefano0000-0002-4622-4240
Bongiorno, Stephen D.0000-0002-0901-2097
Bonino, Raffaella0000-0002-4264-1215
Brez, Alessandro0000-0002-9460-1821
Bucciantini, Niccolò0000-0002-8848-1392
Capitanio, Fiamma0000-0002-6384-3027
Castellano, Simone0000-0003-1111-4292
Ciprini, Stefano0000-0002-0712-2479
Costa, Enrico0000-0003-4925-8523
De Rosa, Alessandra0000-0001-5668-6863
Del Monte, Ettore0000-0002-3013-6334
Di Marco, Alessandro0000-0003-0331-3259
Doroshenko, Victor0000-0001-8162-1105
Dovčiak, Michal0000-0003-0079-1239
Enoto, Teruaki0000-0003-1244-3100
Evangelista, Yuri0000-0001-6096-6710
Fabiani, Sergio0000-0003-1533-0283
Ferrazzoli, Riccardo0000-0003-1074-8605
García, Javier A.0000-0003-3828-2448
Gunji, Shuichi0000-0002-5881-2445
Hayashida, Kiyoshi0000-0002-0110-6136
Heyl, Jeremy0000-0001-9739-367X
Iwakiri, Wataru0000-0002-0207-9010
Karas, Vladimir0000-0002-5760-0459
Kolodziejczak, Jeffery J.0000-0002-0110-6136
La Monaca, Fabio0000-0001-8916-4156
Latronico, Luca0000-0002-0984-1856
Maldera, Simone0000-0002-0698-4421
Manfreda, Alberto0000-0002-0998-4953
Marinucci, Andrea0000-0002-2055-4946
Matt, Giorgio0000-0002-2152-0916
Mizuno, Tsunefumi0000-0001-7263-0296
Muleri, Fabio0000-0003-3331-3794
Ng, Stephen C.-Y.0000-0002-5847-2612
Oppedisano, Chiara0000-0001-6194-4601
Papitto, Alessandro0000-0001-6289-7413
Pavlov, George G.0000-0002-7481-5259
Pesce-Rollins, Melissa0000-0003-1790-8018
Pilia, Maura0000-0001-7397-8091
Possenti, Andrea0000-0001-5902-3731
Ramsey, Brian D.0000-0003-1548-1524
Rankin, John0000-0002-9774-0560
Ratheesh, Ajay0000-0003-0411-4243
Sgró, Carmelo0000-0001-5676-6214
Slane, Patrick0000-0002-6986-6756
Soffitta, Paolo0000-0002-7781-4104
Spandre, Gloria0000-0003-0802-3453
Tamagawa, Toru0000-0002-8801-6263
Taverna, Roberto0000-0002-1768-618X
Tennant, Allyn F.0000-0002-9443-6774
Tombesi, Francesco0000-0002-6562-8654
Trois, Alessio0000-0002-3180-6002
Tsygankov, Sergey0000-0002-9679-0793
Turolla, Roberto0000-0003-3977-8760
Vink, Jacco0000-0002-4708-4219
Weisskopf, Martin C.0000-0002-5270-4240
Wu, Kinwah0000-0002-7568-8765
Xie, Fei0000-0002-0105-5826
Zane, Silvia0000-0001-5326-880X
Additional Information:I.L. thanks the Kavli Institute for the Physics and Mathematics of the Universe for their hospitality while this paper was written. We thank A. Veledina for discussions that helped improve this work. I.L. was supported by the JSPS postdoctoral short-term fellowship programme. 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 (contract NNM15AA18C). The Italian contribution is supported by the Italian Space Agency (Agenzia Spaziale Italiana, ASI) through contract ASI-OHBI-2017-12-I.0, agreements ASI-INAF-2017-12-H0 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). Data from the Steward Observatory spectropolarimetric monitoring project were used. This programme is supported by Fermi Guest Investigator grants NNX08AW56G, NNX09AU10G, NNX12AO93G and NNX15AU81G. This research has made use of data from the RoboPol programme, a collaboration between Caltech, the University of Crete, the Institute of Astrophysics-Foundation for Research and Technology (IA-FORTH), the Inter-University Centre for Astronomy and Astrophysics (IUCAA), the Max Planck Institute for Radioastronomy (MPIfR) and the Nicolaus Copernicus University, which was conducted at Skinakas Observatory in Crete, Greece. The Instituto Astrofísica Andalucía (IAA)-Consejo Superior de Investigaciones Científicas (CSIC) co-authors acknowledge financial support from the Spanish Ministerio de Ciencia e Innovacion (MCINN) through the ‘Center of Excellence Severo Ochoa‘ award for the Instituto de Astrofisica de Andalucia-CSIC (SEV-2017-0709). Acquisition and reduction of the POLAMI and Monitoring AGN with Polarimetry at the Calar Alto Telescopes (MAPCAT) data were supported in part by Ministerio de Ciencia e Innovación (MICINN) through grants AYA2016-80889-P and PID2019-107847RB-C44. The POLAMI observations were carried out at the IRAM 30 m Telescope. IRAM is supported by the National Institute of Sciences of the Universe (INSU)/Scientific Research National Center (CNRS) (France), Max-Planck-Gesellschaft (MPG) (Germany) and Instituto Geográfico Nacional (IGN) (Spain). The research at Boston University was supported in part by National Science Foundation grant AST-2108622, NASA Fermi Guest Investigator grant 80NSSC21K1917 and NASA Swift Guest Investigator grant 80NSSC22K0537. This study uses observations conducted with the 1.8 m Perkins Telescope Observatory in Arizona (USA), which is owned and operated by Boston University. Based on observations obtained at the Hale Telescope, Palomar Observatory as part of a continuing collaboration between the California Institute of Technology, NASA/Jet Propulsion Laboratory (JPL), Yale University and the National Astronomical Observatories of China. This research made use of Photutils, an Astropy package for detection and photometry of astronomical sources60. G.V.P. acknowledges support by NASA through the NASA Hubble Fellowship grant no. HST-HF2-51444.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. Based on 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 Astrofisica de Andalucia (IAA) under a joint agreement with the University of Copenhagen and the Nordic Optical Telescope. V.K. thanks the Vilho, Yrjö and Kalle Väisälä Foundation. J.J. was supported by Academy of Finland project 320085. E.L. was supported by Academy of Finland projects 317636 and 320045. Part of the French contribution was supported by the CNRS and the French spatial agency (CNES). Based on observations collected at the Observatorio de Sierra Nevada, owned and operated by the Instituto de Astrofisica de Andalucia (IAA-CSIC). Based on observations collected at the Centro Astronomico Hispano-Aleman (CAHA), proposal 22A-2.2-015, operated jointly by Junta de Andalucia and Consejo Superior de Investigaciones Cientificas (IAA-CSIC). Open access funding provided by University of Turku (UTU) including Turku University Central Hospital.
Group:Astronomy Department, Infrared Processing and Analysis Center (IPAC), Space Radiation Laboratory
Funding AgencyGrant Number
Japan Society for the Promotion of Science (JSPS)UNSPECIFIED
Agenzia Spaziale Italiana (ASI)ASI-OHBI-2017-12-I.0
Agenzia Spaziale Italiana (ASI)ASI-INAF-2017-12-H0
Agenzia Spaziale Italiana (ASI)ASI-INFN-2017.13-H0
Agenzia Spaziale Italiana (ASI)ASI-INAF-2022-14-HH.0
Agenzia Spaziale Italiana (ASI)ASI-INFN 2021-43-HH.0
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
Istituto Nazionale di Fisica Nucleare (INFN)UNSPECIFIED
Severo OchoaSEV-2017-0709
Ministerio de Economía y Competitividad (MINECO)AYA2016-80889-P
Ministerio de Ciencia e Innovación (MICINN)PID2019-107847RB-C44
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Max-Planck-Gesellschaft (MPG)UNSPECIFIED
Instituto Geográfico Nacional (IGN)UNSPECIFIED
NASA Hubble FellowshipHST-HF2-51444.001-A
Vilho FoundationUNSPECIFIED
Yrjö FoundationUNSPECIFIED
Kalle Väisälä FoundationUNSPECIFIED
Academy of Finland320085
Academy of Finland317636
Academy of Finland320045
Centre National d'Études Spatiales (CNES)UNSPECIFIED
University of TurkuUNSPECIFIED
Turku University Central HospitalUNSPECIFIED
Issue or Number:7937
PubMed Central ID:PMC9684068
Record Number:CaltechAUTHORS:20221212-796684400.32
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:118318
Deposited By: Research Services Depository
Deposited On:13 Jan 2023 15:42
Last Modified:17 Jan 2023 18:04

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