Transverse Oscillations of the M87 Jet Revealed by KaVA Observations

IF 3.2 Q2 ASTRONOMY & ASTROPHYSICS

Galaxies Pub Date : 2023-02-15 DOI:10.3390/galaxies11010033

H. Ro, K. -H. Yi, Yuzhu Cui, M. Kino, K. Hada, T. Kawashima, Y. Mizuno, B. Sohn, F. Tazaki

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引用次数: 1

Abstract

Recent VLBI monitoring has found transverse motions of the M87 jet. However, due to the limited cadence of previous observations, details of the transverse motion have not been fully revealed yet. We have regularly monitored the M87 jet at KVN and VERA Array (KaVA) 22 GHz from December 2013 to June 2016. The average time interval of the observation is ∼0.1 year, which is suitable for tracking short-term structural changes. From these observations, the M87 jet is well represented by double ridge lines in the region 2–12 mas from the core. We found that the ridge lines exhibit transverse oscillations in all observed regions with an average period of 0.94±0.12 years. When the sinusoidal fit is performed, we found that the amplitude of this oscillation is an order of ∼0.1 mas, and the oscillations in the northern and southern limbs are almost in phase. Considering the amplitude, it does not originate from Earth’s parallax. We propose possible scenarios of the transverse oscillation, such as the propagation of jet instabilities or magneto-hydrodynamic (MHD) waves or perturbed mass injection around magnetically dominated accretion flows.

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KaVA观测揭示M87喷流的横向振荡

最近的VLBI监测发现了M87喷气机的横向运动。然而，由于先前观测的有限节奏，横向运动的细节尚未完全揭示。从2013年12月到2016年6月，我们在KVN和VERA阵列(KaVA) 22 GHz定期监测M87喷气机。观测的平均时间间隔为~ 0.1年，适合于跟踪短期结构变化。从这些观测结果来看，M87喷流在距离地核2-12 mas的区域有两条脊线。我们发现脊线在所有观测区域都表现出横向振荡，平均周期为0.94±0.12年。当进行正弦拟合时，我们发现这种振荡的幅度为~ 0.1 mas数量级，南北分支的振荡几乎是同相的。考虑到振幅，它不是来自地球的视差。我们提出了横向振荡的可能情况，例如射流不稳定性或磁流体动力学(MHD)波的传播或磁主导吸积流周围的扰动质量注入。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Galaxies Physics and Astronomy-Astronomy and Astrophysics

CiteScore

4.90

自引率

12.00%

发文量

100

审稿时长

11 weeks

期刊介绍： Es una revista internacional de acceso abierto revisada por pares que proporciona un foro avanzado para estudios relacionados con astronomía, astrofísica y cosmología. Areas temáticas Astronomía Astrofísica Cosmología Astronomía observacional: radio, infrarrojo, óptico, rayos X, neutrino, etc. Ciencia planetaria Equipos y tecnologías de astronomía. Ingeniería Aeroespacial Análisis de datos astronómicos. Astroquímica y Astrobiología. Arqueoastronomía Historia de la astronomía y cosmología. Problemas filosóficos en cosmología.