2004/01/15 by D. C. Homan, J. F. C. Wardle · 45 citations
Physics and Astronomy · #Active galactic nucleus #Astrophysics #Astrophysics and Cosmic Phenomena #Circular polarization #Faraday effect #Galaxy #Gamma-ray bursts and supernovae #Linear polarization #Magnetic field #Optics #Physics #Polarization (electrochemistry) #Polarization in astronomy #Radiation #Radio Astronomy Observations and Technology #Radio galaxy #Synchrotron radiation #Very Long Baseline Array #Very-long-baseline interferometry #astro-ph
paper · pdf · doi:10.1086/382273
published in The Astrophysical Journal 602(1), L13-L16 (IOP Publishing) · 4 pages, accepted in ApJ Letters
arxiv created 2004/01/15 · openalex publication_date 2004/01/29 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
We present multifrequency, high-resolution, Very Long Baseline Array circular polarization images of the radio source 3C 84 in the center of NGC 1275. Our images reveal a complex distribution of circular polarization in the inner parsec of the radio jet, with local levels exceeding 3% polarization, the highest yet detected with VLBI techniques. The circular polarization changes sign along the jet, making 3C 84 also the first radio jet to show both signs of circular polarization simultaneously. The spectrum and changing sign of the circular polarization indicate that it is unlikely to be purely intrinsic to the emitted synchrotron radiation. The Faraday conversion process makes a significant and perhaps dominant contribution to the circular polarization, and the observed spectrum suggests that the conversion process is near saturation. The sign change in the circular polarization along the jet may result from this saturation or may be due to a change in magnetic field order after an apparent bend in the jet. From the small spatial scales probed here, ≃0.15 pc, and the comparably high levels of circular polarization inferred for the intraday variable source PKS 1519-273, we suggest a connection between small spatial scales and efficient production of circular polarization.