A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Where within the 3C 84 jet are γ-rays produced?; 
Tekijät: Paraschos, Georgios F.; Liodakis, Ioannis; Jorstad, Svetlana; Kovalev, Yuri Y.; Chakraborty, Sudip; Marin, Frédéric; Ehlert, Steven R.; Traianou, Efthalia; Debbrecht, Lena C.; Agudo, Iván; Barnouin, Thibault; Casey, Jacob J.; Di Gesu, Laura; Kaaret, Philip; Kim, Dawoon E.; Kislat, Fabian; Ratheesh, Ajay; Saade, M. Lynne; Tombesi, Francesco; Marscher, Alan; Gómez, José-Luis; Pushkarev, Alexander B.; Savolainen, Tuomas; Myserlis, Ioannis; Gurwell, Mark; Keating, Garrett; Rao, Ramprasad; Kang, Sincheol; Lee, Sang-Sung; Kim, Sanghyun; Yeon, Cheong Whee; Jeong, Hyeon-Woo; Song, Chanwoo; Li, Shan; Nam, Myeong-Seok; Álvarez-Ortega, Diego; Casadio, Carolina; Chen, Chien-Ting; Costa, Enrico; Churazov, Eugene; Ferrazzoli, Riccardo; Galanti, Giorgio; Khabibullin, Ildar; O’Dell, Stephen L.; Pacciani, Luigi; Roncadelli, Marco; Roberts, Oliver J.; Soffitta, Paolo; Swartz, Douglas A.; Tavecchio, Fabrizio; Weisskopf, Martin C.; Zhuravleva, Irina
Kustantaja: EDP Sciences
Julkaisuvuosi: 2026
Lehti: Astronomy and Astrophysics
Artikkelin numero: A92
Vuosikerta: 709
ISSN: 0004-6361
eISSN: 1432-0746
DOI: https://doi.org/10.1051/0004-6361/202659250
Julkaisun avoimuus kirjaamishetkellä: Avoimesti saatavilla
Julkaisukanavan avoimuus : Kokonaan avoin julkaisukanava
Verkko-osoite: https://doi.org/10.1051/0004-6361/202659250
Rinnakkaistallenteen osoite: https://research.utu.fi/converis/portal/detail/Publication/524887595
Rinnakkaistallenteen lisenssi: CC BY
Rinnakkaistallennetun julkaisun versio: Kustantajan versio
The location in which γ-ray are created and emitted within extra-galactic jets is a matter of active debate. One particularly well-suited source for determining the location is the nearby bright radio galaxy 3C 84, harbouring a powerful jet. We investigated the origin of γ-rays that were measured during a recent γ-ray flare by analysing the linear polarisation signal of close-in-time very long baseline interferometry (VLBI) observations at centimetre and millimetre wavelengths. While 3C 84 is almost unpolarised overall, we find that close in time to the γ-ray flare peak regions at parsec-scale distances from the central engine, the linear polarisation increases fractionally. Under the physically well-motivated assumption of a causal relation between this polarisation enhancement and the γ-ray flare, and combined with insights from concurrent X-ray polarisation measurements, a physically motivated scenario is that the γ-rays are created in this region, in a process consistent with the synchrotron self-Compton mechanism.
Avainsanat:
galaxies: individual: 3C 84, techniques: high angular resolution, techniques: interferometric, techniques: polarimetric
Ladattava julkaisu This is an electronic reprint of the original article. |  |
Julkaisussa olevat rahoitustiedot:
This research is supported by the European Research Council advanced grant “M2FINDERS – Mapping Magnetic Fields with INterferometry Down to Event hoRizon Scales” (Grant No. 101018682). I. Liodakis was funded by the European Union ERC-2022-STG – BOOTES – 101076343. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council Executive Agency. Neither the European Union nor the granting authority can be held responsible for them. Y. Y. Kovalev was supported by the MuSES project, which has received funding from the European Union (ERC grant agreement No 101142396). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or ERCEA. Neither the European Union nor the granting authority can be held responsible for them. A. B. Pushkarev is supported in the framework of the State project ‘Science’ by the Ministry of Science and Higher Education of the Russian Federation under the contract 075-15-2024-541. C. Casadio and D. Álvarez-Ortega acknowledge support from the European Research Council (ERC) under the Horizon ERC Grants 2021 programme under grant agreement No.101040021. The University of New Hampshire group is supported in part by NASA Astrophysics Astrophysics Data Analysis Program grant 80NSSC24K0636. The POLAMI observations reported here were carried out at the IRAM 30 m Telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). The Submillimeter Array (SMA) is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. Maunakea, the location of the SMA, is a culturally important site for the indigenous Hawaiian people; we are privileged to study the cosmos from its summit. The KVN is a facility operated by the Korea Astronomy and Space Science Institute. The KVN operations are supported by KREONET (Korea Research Environment Open NETwork) which is managed and operated by KISTI (Korea Institute of Science and Technology Information). S. Kang, S.-S. Lee, W. Y. Cheong, S.-H. Kim, and H.-W. Jeong were supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MIST) (2020R1A2C2009003, RS-2025-00562700). The IAA-CSIC co-authors acknowledge financial support from the Spanish “Ministerio de Ciencia e Innovación” (MCIN/AEI/ 10.13039/501100011033) through the Center of Excellence Severo Ochoa award for the Instituto de Astrofíisica de Andalucía-CSIC (CEX2021-001131-S), and through grants PID2019-107847RB-C44 and PID2022-139117NB-C44. This study makes use of VLBA data from the VLBA-BU Blazar Monitoring Program (BEAM-ME and VLBA-BU-BLAZAR; http://www.bu.edu/blazars/BEAM-ME.html), funded by NASA through the Fermi Guest Investigator Program. The VLBA is an instrument of the National Radio Astronomy Observatory. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated by Associated Universities, Inc. This research has made use of data from the MOJAVE database that is maintained by the MOJAVE team (Lister et al. 2018). This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This research has also made use of NASA’s Astrophysics Data System Bibliographic Services. Finally, this research made use of the following python packages: numpy (Harris et al. 2020), scipy (Virtanen et al. 2020), matplotlib (Hunter 2007), astropy (Astropy Collaboration 2013, 2018) and Uncertainties: a Python package for calculations with uncertainties.
