Magnetic Field Geometry of the Gamma-Ray Binary PSR B1259–63 Revealed via X-Ray Polarization

Philip Kaaret; Oliver J. Roberts; Steven R. Ehlert; Douglas A. Swartz; Martin C. Weisskopf; Ioannis Liodakis; M. Lynne Saade; Stephen L. O’Dell; Chien-Ting Chen

doi:10.3847/2041-8213/ad7ba6

The Astrophysical Journal Letters (Jan 2024)

Magnetic Field Geometry of the Gamma-Ray Binary PSR B1259–63 Revealed via X-Ray Polarization

Philip Kaaret,
Oliver J. Roberts,
Steven R. Ehlert,
Douglas A. Swartz,
Martin C. Weisskopf,
Ioannis Liodakis,
M. Lynne Saade,
Stephen L. O’Dell,
Chien-Ting Chen

Affiliations

Philip Kaaret: ORCiD; NASA Marshall Space Flight Center , Huntsville, AL 35812, USA
Oliver J. Roberts: ORCiD; Science and Technology Institute, Universities Space Research Association , Huntsville, AL 35805, USA
Steven R. Ehlert: ORCiD; NASA Marshall Space Flight Center , Huntsville, AL 35812, USA
Douglas A. Swartz: ORCiD; Science and Technology Institute, Universities Space Research Association , Huntsville, AL 35805, USA
Martin C. Weisskopf: ORCiD; NASA Marshall Space Flight Center , Huntsville, AL 35812, USA
Ioannis Liodakis: ORCiD; NASA Marshall Space Flight Center , Huntsville, AL 35812, USA; Institute of Astrophysics, Foundation for Research and Technology-Hellas , GR-70013 Heraklion, Greece
M. Lynne Saade: ORCiD; Science and Technology Institute, Universities Space Research Association , Huntsville, AL 35805, USA
Stephen L. O’Dell: ORCiD; NASA Marshall Space Flight Center , Huntsville, AL 35812, USA
Chien-Ting Chen: ORCiD; Science and Technology Institute, Universities Space Research Association , Huntsville, AL 35805, USA

DOI: https://doi.org/10.3847/2041-8213/ad7ba6
Journal volume & issue: Vol. 974, no. 1
p. L1

Abstract

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Some X-ray binaries containing an energetic pulsar in orbit around a normal star accelerate particles to high energies in the shock cone formed where the pulsar and stellar winds collide. The magnetic field geometry in the acceleration region in such binaries is unknown. We performed the first measurement of the polarization of the X-ray synchrotron emission from a gamma-ray-emitting binary system. We observed PSR B1259–63 with the Imaging X-ray Polarimetry Explorer during an X-ray bright phase following the periastron passage in 2024 June. X-ray polarization is detected with a polarization degree of 8.3% ± 1.5% at a significance of 5.3 σ . The X-ray polarization angle is aligned with the axis of the shock cone at the time of the observation. This indicates that the predominant component of the magnetic field in the acceleration region is oriented perpendicular to the shock-cone axis.

Published in The Astrophysical Journal Letters

ISSN: 2041-8205 (Print); 2041-8213 (Online)
Publisher: IOP Publishing
Country of publisher: United Kingdom
LCC subjects: Science: Astronomy: Astrophysics
Website: https://iopscience.iop.org/journal/2041-8205

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