Kinematics of the M87 Jet in the Collimation Zone: Gradual Acceleration and Velocity Stratification
文献类型:期刊论文
作者 | Park, Jongho16,17; Hada, Kazuhiro14,15; Kino, Motoki12,13; Nakamura, Masanori17; Hodgson, Jeffrey11; Ro, Hyunwook10; Cui, Yuzhu; Asada, Keiichi; Algaba, Juan-Carlos9; Sawada-Satoh, Satoko8 |
刊名 | ASTROPHYSICAL JOURNAL |
出版日期 | 2019-12-20 |
卷号 | 887期号:2页码:27 |
ISSN号 | 0004-637X |
DOI | 10.3847/1538-4357/ab5584 |
通讯作者 | Park, Jongho(jpark@asiaa.sinica.edu.tw) |
英文摘要 | We study the kinematics of the M87 jet using the first-year data of the KVN and VERA Array (KaVA) large program, which has densely monitored the jet at 22 and 43 GHz since 2016. We find that the apparent jet speeds generally increase from approximate to 0.3c at approximate to 0.5 mas from the jet base to approximate to 2.7c at approximate to 20 mas, indicating that the jet is accelerated from subluminal to superluminal speeds on these scales. We perform a complementary jet kinematic analysis by using archival Very Long Baseline Array monitoring data observed in 2005-2009 at 1.7 GHz and find that the jet is moving at relativistic speeds up to approximate to 5.8c at distances of 200-410 mas. We combine the two kinematic results and find that the jet is gradually accelerated over a broad distance range that coincides with the jet collimation zone, implying that conversion of Poynting flux to kinetic energy flux takes place. If the jet emission consists of a single streamline, the observed trend of jet acceleration (Gamma alpha z(0.16 +/- 0.01)) is relatively slow compared to models of a highly magnetized jet. This indicates that Poynting flux conversion through the differential collimation of poloidal magnetic fields may be less efficient than expected. However, we find a nonnegligible dispersion in the observed speeds for a given jet distance, making it difficult to describe the jet velocity field with a single power-law acceleration function. We discuss the possibility that the jet emission consists of multiple streamlines following different acceleration profiles, resulting in jet velocity stratification. |
WOS关键词 | RELATIVISTIC MAGNETOHYDRODYNAMIC SIMULATIONS ; ACTIVE GALACTIC NUCLEUS ; GAMMA-RAY ; RADIO JET ; BLACK-HOLE ; MAGNETIC ACCELERATION ; INNER JET ; AGN JETS ; SCALE ; ACCRETION |
WOS研究方向 | Astronomy & Astrophysics |
语种 | 英语 |
出版者 | IOP PUBLISHING LTD |
WOS记录号 | WOS:000506012000041 |
源URL | [http://libir.pmo.ac.cn/handle/332002/35601] |
专题 | 中国科学院紫金山天文台 |
通讯作者 | Park, Jongho |
作者单位 | 1.Toyo Univ, Bunkyo Ku, 5-28-20 Hakusan, Tokyo 1128606, Japan 2.Kyung Hee Univ, Dept Astron & Space Sci, Yongin 17104, Gyeonggi Do, South Korea 3.Univ Chinese Acad Sci, 19A Yuquanlu, Beijing 100049, Peoples R China 4.MIT, Haystack Observ, 99 Millstone Rd, Westford, MA 01886 USA 5.Chinese Acad Sci, Key Lab Radio Astron, Nanjing 210008, Peoples R China 6.Chinese Acad Sci, Shanghai Astron Observ, Shanghai 200030, Peoples R China 7.Univ Sci Technol, Dept Astron Space Sci, 217 Gajeong Ro, Daejeon, South Korea 8.Yamaguchi Univ, Grad Sch Sci & Technol Innovat, Yoshida 1677-1, Yamaguchi, Yamaguchi 7538512, Japan 9.Univ Malaya, Dept Phys, Fac Sci, Kuala Lumpur 50603, Malaysia 10.Yonsei Univ, Dept Astron, 134 Shinchondong, Seoul 120749, South Korea |
推荐引用方式 GB/T 7714 | Park, Jongho,Hada, Kazuhiro,Kino, Motoki,et al. Kinematics of the M87 Jet in the Collimation Zone: Gradual Acceleration and Velocity Stratification[J]. ASTROPHYSICAL JOURNAL,2019,887(2):27. |
APA | Park, Jongho.,Hada, Kazuhiro.,Kino, Motoki.,Nakamura, Masanori.,Hodgson, Jeffrey.,...&Hagiwara, Yoshiaki.(2019).Kinematics of the M87 Jet in the Collimation Zone: Gradual Acceleration and Velocity Stratification.ASTROPHYSICAL JOURNAL,887(2),27. |
MLA | Park, Jongho,et al."Kinematics of the M87 Jet in the Collimation Zone: Gradual Acceleration and Velocity Stratification".ASTROPHYSICAL JOURNAL 887.2(2019):27. |
入库方式: OAI收割
来源:紫金山天文台
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