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 -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 Msec that coincides with a flare in -rays. This is the longest observation for a radio-loud active galaxy that allowed us to reach unprecedented sensitivity, leading to the detection of an X-ray polarization degree of ( confidence) at an X-ray electric vector polarization angle of , that 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 places downstream, away from the supermassive black hole.
Cite
@article{arxiv.2510.16109,
title = {Detection of Compton scattering in the jet of 3C 84},
author = {Ioannis Liodakis and Sudip Chakraborty and Frédéric Marin and Steven R. Ehlert and Thibault Barnouin and Pouya M. Kouch and Kari Nilsson and Elina Lindfors and Tapio Pursimo and Georgios F. Paraschos and Riccardo Middei and Anna Trindade Falcão and Svetlana Jorstad and Iván Agudo and Yuri Y. Kovalev and Jacob J. Casey and Laura Di Gesu and Philip Kaaret and Dawoon E. Kim and Fabian Kislat and Ajay Ratheesh and M. Lynne Saade and Francesco Tombesi and Alan Marscher and Francisco José Aceituno and Giacomo Bonnoli and Víctor Casanova and Gabriel Emery and Juan Escudero Pedrosa and Daniel Morcuende and Jorge Otero-Santos and Alfredo Sota and Vilppu Piirola and Rumen Bachev and Anton Strigachev and George A. Borman and Tatiana S. Grishina and Vladimir A. Hagen-Thorn and Evgenia N. Kopatskaya and Elena G. Larionova and Daria A. Morozova and Sergey S. Savchenko and Ekaterina V. Shishkina and Ivan S. Troitskiy and Yulia V. Troitskaya and Andrey A. Vasilyev and Alexey V. Zhovtan and Ioannis Myserlis and Mark Gurwell and Garrett Keating and Ramprasad Rao and Sincheol Kang and Sang-Sung Lee and Sanghyun Kim and Whee Yeon Cheong and Hyeon-Woo Jeong and Chanwoo Song and Shan Li and Myeong-Seok Nam and Diego Álvarez-Ortega and Carolina Casadio and Emmanouil Angelakis and Alexander Kraus and Jenni Jormanainen and Vandad Fallah Ramazani and Chien-Ting Chen and Enrico Costa and Eugene Churazov and Riccardo Ferrazzoli and Giorgio Galanti and Ildar Khabibulin and Stephen L. O'Dell and Luigi Pacciani and Marco Roncadelli and Oliver J. Roberts and Paolo Soffitta and Douglas A. Swartz and Fabrizio Tavecchio and Martin C. Weisskopf and Irina Zhuravleva},
journal= {arXiv preprint arXiv:2510.16109},
year = {2025}
}
Comments
21 pages, 13 figure, 1 Table, published in APJL