Transverse Oscillations and Wave Propagation in the Magnetically Dominated M87 Jet
Abstract We present an in-depth analysis of the transverse oscillations in the M87 jet, as identified in our previous study, which reported oscillatory patterns with a characteristic period of ∼1 yr in the edge-brightened jet structure extending up to 12 mas from the core. This work is based on high-cadence KaVA 22 GHz observations conducted from 2013 December to 2016 June. By analyzing the transverse velocity profiles and the spatial evolution of the oscillations, we find that the oscillations propagate downstream along the jet, with a wavelength of ∼9–10 mas. A single-mode sinusoidal wave model applied to the ridgelines successfully reproduces the observed transverse oscillations and yields superluminal wave speeds of ∼2.7–2.9 c , consistent with the bulk jet velocity in this region. These findings suggest that the transverse oscillations may be interpreted either as transverse MHD waves—possibly excited by jet precession, nutation, or quasiperiodic magnetic flux eruptions near the central engine—or as manifestations of jet instabilities, such as current-driven instabilities. Further investigation is required to distinguish between these scenarios and to clarify the dominant physical mechanism.
Authors
- Bong Won Sohn (ORCID: https://orcid.org/0000-0002-4148-8378)
- Hyunwook Ro (ORCID: https://orcid.org/0000-0002-7322-6436)
- Kunwoo Yi (ORCID: https://orcid.org/0009-0007-8554-4507)
- M. Kino
- Yuzhu Cui
- Kazuhiro Hada
- Tomohisa Kawashima
- Jongho Park
- Yosuke Mizuno
Institutions
- Kogakuin University (JP)
- Institute of Astronomy and Astrophysics, Academia Sinica (TW)
- Shanghai Jiao Tong University (CN)
- Yonsei University (KR)
- Korea Astronomy and Space Science Institute (KR)
- Nagoya City University (JP)
- Kyung Hee University (KR)
- Central China Normal University (CN)
- Kavli Institute for Particle Astrophysics and Cosmology (US)
- National Institute of Technology, Ichinoseki College (JP)
- Mizuho (Japan) (JP)
- National Astronomical Observatory of Japan (JP)
- Korea University of Science and Technology (KR)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2026-03-02
- DOI
- https://doi.org/10.3847/1538-4357/ae355b
- Primary Topic
- Astrophysics and Cosmic Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Daiko Foundation
- POSCO TJ Park Foundation
- National Research Foundation
- Ministry of Education, Culture, Sports, Science and Technology
- National Natural Science Foundation of China
- China Postdoctoral Science Foundation
- Korea Astronomy and Space Science Institute
- National Research Foundation of Korea
- National Astronomical Observatory of Japan
- Nagoya City University
- Ministry of Science and ICT, South Korea
- Japan Society for the Promotion of Science