Detection of Compton Scattering in the Jet of 3C 84
Abstract 3C 84 is the brightest cluster galaxy in the Perseus Cluster. It is among the closest radio-loud active galaxies and among the very few that can be detected from low-frequency radio up to TeV γ -rays. Here we report on the first X-ray polarization observation of 3C 84 with the Imaging X-ray Polarimetry Explorer, for a total of 2.2 Ms coinciding with a flare in γ -rays. This is the longest observation for a radio-loud active galaxy, which allowed us to reach unprecedented sensitivity, leading to the detection of an X-ray polarization degree of Π X = 4.2% ± 1.3% (∼3.2 σ confidence) at an X-ray electric vector polarization angle of ψ X = 163° ± 9°, which is aligned with the radio jet direction on the sky. Optical polarization observations show fast variability about the jet axis as well. Our results strongly favor models in which X-rays are produced by Compton scattering from relativistic electrons—specifically synchrotron self-Compton—that takes place downstream, away from the supermassive black hole.
Authors
- Fabian Kislat (ORCID: https://orcid.org/0000-0001-7477-0380)
- Laura Di Gesu (ORCID: https://orcid.org/0000-0002-5614-5028)
- Thibault Barnouin (ORCID: https://orcid.org/0000-0003-1340-5675)
- Dawoon E. Kim (ORCID: https://orcid.org/0000-0001-5717-3736)
- A. A. Vasilyev (ORCID: https://orcid.org/0000-0002-8293-0214)
- Daniel Morcuende (ORCID: https://orcid.org/0000-0001-9400-0922)
- Chien‐Ting Chen (ORCID: https://orcid.org/0000-0002-4945-5079)
- A. Sota (ORCID: https://orcid.org/0000-0002-9404-6952)
- A. Kraus (ORCID: https://orcid.org/0000-0002-4184-9372)
- Ioannis Liodakis (ORCID: https://orcid.org/0000-0001-9200-4006)
- А. В. Жовтан
- Pouya M. Kouch (ORCID: https://orcid.org/0000-0002-9328-2750)
- Y. Y. Kovalev (ORCID: https://orcid.org/0000-0001-9303-3263)
- E. Costa (ORCID: https://orcid.org/0000-0003-4925-8523)
- Garrett K. Keating (ORCID: https://orcid.org/0000-0002-3490-146X)
- F. Tavecchio (ORCID: https://orcid.org/0000-0003-0256-0995)
- E. Angelakis (ORCID: https://orcid.org/0000-0001-7327-5441)
- Diego Álvarez-Ortega (ORCID: https://orcid.org/0000-0002-9998-5238)
- Sincheol Kang (ORCID: https://orcid.org/0000-0002-0112-4836)
- M. Lynne Saade (ORCID: https://orcid.org/0000-0001-7163-7015)
- P. Soffitta (ORCID: https://orcid.org/0000-0002-7781-4104)
- A. Strigachev
- Jorge Otero-Santos (ORCID: https://orcid.org/0000-0002-4241-5875)
- Martin C. Weisskopf (ORCID: https://orcid.org/0000-0002-5270-4240)
- Е. Г. Ларионова (ORCID: https://orcid.org/0000-0002-2471-6500)
- Yu. V. Troitskaya (ORCID: https://orcid.org/0000-0002-9907-9876)
- С. С. Савченко (ORCID: https://orcid.org/0000-0003-4147-3851)
- V. Fallah Ramazanı (ORCID: https://orcid.org/0000-0001-8991-7744)
- Myung-Jin Nam
- O. J. Roberts (ORCID: https://orcid.org/0000-0002-7150-9061)
- I. Myserlis (ORCID: https://orcid.org/0000-0003-3025-9497)
- T. S. Grishina (ORCID: https://orcid.org/0000-0002-3953-6676)
- I. Agudo (ORCID: https://orcid.org/0000-0002-3777-6182)
- Francesco Tombesi (ORCID: https://orcid.org/0000-0002-6562-8654)
- Ramprasad Rao (ORCID: https://orcid.org/0000-0002-1407-7944)
- Frédéric Marin (ORCID: https://orcid.org/0000-0003-4952-0835)
- D. A. Morozova (ORCID: https://orcid.org/0000-0002-9407-7804)
- Steven R. Ehlert (ORCID: https://orcid.org/0000-0003-4420-2838)
- Sudip Chakraborty (ORCID: https://orcid.org/0000-0003-4872-8159)
- Stephen L. O’Dell (ORCID: https://orcid.org/0000-0002-1868-8056)
- Hyeon‐Woo Jeong (ORCID: https://orcid.org/0009-0005-7629-8450)
- F. J. Aceituno (ORCID: https://orcid.org/0000-0001-8074-4760)
- E. N. Kopatskaya (ORCID: https://orcid.org/0000-0001-9518-337X)
- I. S. Troitskiy (ORCID: https://orcid.org/0000-0002-4218-0148)
- Riccardo Ferrazzoli (ORCID: https://orcid.org/0000-0003-1074-8605)
- Sang-Sung Lee (ORCID: https://orcid.org/0000-0002-6269-594X)
- G. Bonnoli (ORCID: https://orcid.org/0000-0003-2464-9077)
- Giorgio Galanti (ORCID: https://orcid.org/0000-0001-7254-3029)
- E. Lindfors (ORCID: https://orcid.org/0000-0002-9155-6199)
- V. Casanova (ORCID: https://orcid.org/0000-0003-2036-8999)
- K. Nilsson (ORCID: https://orcid.org/0000-0002-1445-8683)
- Г. А. Борман (ORCID: https://orcid.org/0000-0002-7262-6710)
- Douglas A. Swartz (ORCID: https://orcid.org/0000-0002-2954-4461)
- Chanwoo Song (ORCID: https://orcid.org/0009-0003-8767-7080)
- Whee Yeon Cheong (ORCID: https://orcid.org/0009-0002-1871-5824)
- Georgios Filippos Paraschos (ORCID: https://orcid.org/0000-0001-6757-3098)
- C. Casadio (ORCID: https://orcid.org/0000-0003-1117-2863)
- Jenni Jormanainen (ORCID: https://orcid.org/0000-0003-4519-7751)
- R. Middei (ORCID: https://orcid.org/0000-0001-9815-9092)
- E. Churazov (ORCID: https://orcid.org/0000-0002-0322-884X)
- Mark Gurwell (ORCID: https://orcid.org/0000-0003-0685-3621)
- L. Pacciani (ORCID: https://orcid.org/0000-0001-6897-5996)
- Alan P. Marscher (ORCID: https://orcid.org/0000-0001-7396-3332)
- P. Kaaret (ORCID: https://orcid.org/0000-0002-3638-0637)
- Ajay Ratheesh (ORCID: https://orcid.org/0000-0003-0411-4243)
- Anna Trindade Falcão (ORCID: https://orcid.org/0000-0001-8112-3464)
- R. Bachev (ORCID: https://orcid.org/0000-0002-0766-864X)
- M. Roncadelli (ORCID: https://orcid.org/0000-0003-2192-3472)
- V. Piirola (ORCID: https://orcid.org/0000-0003-0186-206X)
- Shan Li (ORCID: https://orcid.org/0000-0002-3095-3721)
- Sang-Hyun Kim (ORCID: https://orcid.org/0000-0001-7556-8504)
- V. A. Hagen-Thorn (ORCID: https://orcid.org/0000-0002-6431-8590)
- Juan Escudero (ORCID: https://orcid.org/0000-0002-4131-655X)
- Tapio Pursimo
- Jacob Casey (ORCID: https://orcid.org/0009-0009-3051-6570)
- Gabriel Emery
- S. G. Jorstad (ORCID: https://orcid.org/0000-0001-9522-5453)
- Ekaterina V. Shishkina (ORCID: https://orcid.org/0009-0002-2440-2947)
- Ildar Khabibulin
Publication Details
- Journal
- The Astrophysical Journal Letters
- Published
- 2025-11-11
- DOI
- https://doi.org/10.3847/2041-8213/ae157d
- Primary Topic
- Astrophysical Phenomena and Observations
- Type
- article
- Field-Weighted Citation Impact
- 0.00