A polarized view of the young pulsar wind nebula 3C 58 with IXPE

¹ INAF – Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Firenze, Italy.
² Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, Via Sansone 1, 50019 Sesto Fiorentino, Italy
³ Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, Via Sansone 1, 50019 Sesto Fiorentino, Italy
⁴ Department of Physics and Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305, USA
⁵ Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning 530004, China
⁶ Department of Physics, The University of Hong Kong, Pokfulam, Hong Kong
⁷ Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa, Italy
⁸ Graduate Institute of Astronomy, National Central University, 300 Zhongda Road, Zhongli, Taoyuan 32001, Taiwan
⁹ Laboratory for Space Research, The University of Hong Kong, Cyberport 4, Hong Kong
¹⁰ Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
¹¹ Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
¹² University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100049, China
¹³ INAF Osservatorio Astronomico di Cagliari, Via della Scienza 5, 09047 Selargius (CA), Italy
¹⁴ Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803, USA

^★ Corresponding author: niccolo.bucciantini@inaf.it

Received: 21 February 2025
Accepted: 7 May 2025

Abstract

Pulsar wind nebulae (PWNe) are among the most efficient particle accelerators in the Universe; however, the physical conditions and magnetic geometry in their inner regions remain poorly understood. X-ray polarization now provides a unique opportunity to investigate the magnetic field structure and turbulence properties close to the sites where high energy particles are accelerated. Here, we report on recent X-ray polarization measurements of the PWN 3C 58 by the International X-ray Polarimeter Explorer (IXPE). 3C 58 is a young system that displays a characteristic jet-torus structure that, unlike those in other PWNe, is observed almost edge-on. This nebula exhibits a high level of integrated polarization, approximately 22%, at an angle near 97°, with an implied magnetic field oriented parallel to the major axis of the inner torus. This suggests a toroidal magnetic geometry with little turbulence in the interior and an intrinsic level of polarization possibly approaching the theoretical limit for synchrotron emission. No significant detection of a polarized signal from the associated pulsar was found. These results confirm that the internal structure of young PWNe is far less turbulent than previously predicted and is at odds with multidimensional numerical simulations.