Unveiling blazar synchrotron emission: A multiwavelength polarimetric study of high-synchrotron and low-synchrotron peaked populations

Capecchiacci S, Liodakis I, Middei R, Kim DE, Di Gesu L, Agudo I, Agís-González B, Arbet-Engels A, Blinov D, Chen CT, Ehlert SR, Gau E, Heckmann L, Hu K, Jorstad SG, Kaaret P, Kouch PM, Krawczynski H, Lindfors E, Marin F, Marscher AP, Myserlis I, Oadell SL, Pacciani L, Paneque D, Perri M, Puccetti S, Saade ML, Tavecchio F, Tennant AF, Traianou E, Weisskopf MC, Wu K, Aceituno FJ, Bonnoli G, Casanova V, Emery G, Escudero J, Morcuende D, Otero-Santos J, Sota A, Piirola V, Borman GA, Kopatskaya EN, Larionova EG, Morozova DA, Shishkina EV, Savchenko SS, Vasilyev AA, Grishina TS, Troitskiy IS, Zhovtan AV, McCall C, Jermak HE, Steele IA, Bachev R, Strigachev A, Imazawa R, Sasada M, Fukazawa Y, Kawabata KS, Uemura M, Mizuno T, Nakaoka T, Tochihara S, Akai T, Akitaya H, Berdyugin AV, Kagitani M, Kravtsov V, Poutanen J, Sakanoi T, Álvarez-Ortega D, Casadio C, Kang S, Lee SS, Kim S, Cheong WY, Jeong HW, Song C, Li S, Nam MS, Gurwell M, Keating G, Rao R, Angelakis E, Kraus A, Benke P, Debbrecht L, Eich J, Eppel F, Gokus A, Hämmerich S, HeDörfer J, Kadler M, Kirchner D, Paraschos GF, Rösch F, Schulga W (2025)

Publication Type: Journal article

Publication year: 2025

Journal

Book Volume: 703

Article Number: A19

DOI: 10.1051/0004-6361/202555392

Abstract

The polarimetric properties of blazars enable us to place constraints on the acceleration mechanisms that fuel their powerful jets. By studying the multiwavelength polarimetric behaviour of high-synchrotron peaked (HSP) and low-synchrotron peaked (LSP) blazars, we aim to explore differences in their emission mechanisms and magnetic field structure in the acceleration region. In this study, we take advantage of several X-ray polarisation observations of HSP by the IXPE, including four new observations of Mrk 501, along with optical polarisation observations of LSP from RoboPol and other instruments. We find that the polarisation degree (PD) distribution of HSP in X-rays is systematically higher than in optical and mm-radio wavelengths, as reported in previous IXPE publications. The distribution of the X-ray electric vector position angles (PA) is centred around the jet axis with most of the observations consistent with zero difference within uncertainties. In fact, the distribution of the offset of the PA from the jet axis is consistent between the LSP and HSP populations (with PA measured in optical for the first, X-ray for the latter), suggesting a common magnetic field structure close to the acceleration region. These results offer strong support for the emerging energy stratified scenario of particle acceleration followed by energy loss in blazar jets.

Authors with CRIS profile

Involved external institutions

Julius-Maximilians-Universität Würzburg Germany (DE) Saint Petersburg State University (SPbU) / Санкт-Петербургский государственный университет (СПбГУ) Russian Federation (RU) Max-Planck-Institut für Physik (Werner-Heisenberg-Institut, MPP) / Max Planck Institute for Physics Germany (DE) Washington University in St. Louis United States (USA) (US) Boston University United States (USA) (US) Turku University Hospital / Turun yliopistollinen keskussairaala (TYKS) Finland (FI) Crimean Astrophysical Observatory (CrAO) Ukraine (UA) Liverpool John Moores University (JMU) United Kingdom (GB) Université de Strasbourg (UDS) France (FR) Foundation for Research and Technology-Hellas (FORTH) / Ίδρυμα Τεχνολογίας και Έρευνας Greece (GR) National Aeronautics and Space Administration (NASA) United States (USA) (US) National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF) Italy (IT) Korea Astronomy and Space Science Institute (KASI) Korea, Republic of (KR) Hiroshima University / 広島大学 Japan (JP) Tohoku University Japan (JP) Italian Space Agency / Agenzia Spaziale Italiana (ASI) Italy (IT) Max-Planck-Institut für Radioastronomie / Max Planck Institute for Radio Astronomy Germany (DE) Institute of Astrophysics of Andalusia / Instituto de Astrofísica de Andalucía (IAA-CSIC) Spain (ES) Science and Technology Institute United States (USA) (US) Chiba Institute of Technology / 千葉工業大学 Japan (JP) Ruprecht-Karls-Universität Heidelberg Germany (DE) Institute of Astronomy and National Astronomical Observatory / Институт по астрономия Bulgaria (BG) Smithsonian Institution United States (USA) (US) IRAM : Institut de Radioastronomie Millimétrique France (FR) University College London (UCL) United Kingdom (GB) National and Kapodistrian University of Athens Greece (GR) Institute of Science Tokyo (ISCT) / 東京科学大学 Japan (JP)

How to cite

APA:

Capecchiacci, S., Liodakis, I., Middei, R., Kim, D.E., Di Gesu, L., Agudo, I.,... Schulga, W. (2025). Unveiling blazar synchrotron emission: A multiwavelength polarimetric study of high-synchrotron and low-synchrotron peaked populations. Astronomy & Astrophysics, 703. https://doi.org/10.1051/0004-6361/202555392

MLA:

Capecchiacci, Sara, et al. "Unveiling blazar synchrotron emission: A multiwavelength polarimetric study of high-synchrotron and low-synchrotron peaked populations." Astronomy & Astrophysics 703 (2025).

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