Detections of Nearly Bias-free Core Shifts with 5-30 μas Precisions at 8-43 GHz in BL Lacertae
文献类型：期刊论文
| 作者 | Liu, Niu1,2; Yang, Jun3; Cheng, Xiaopeng4; Zeng, Ai-Ling5; Chen W(陈文)6; Yang, Xiao-Long7; Hong, Xiaoyu7,8; Zhang, Xia-Xuan1,2; Liu, Jia-Cheng1,2; Zhu, Zi1,2,9 |
| 刊名 | ASTROPHYSICAL JOURNAL
 |
| 出版日期 | 2026-05-20 |
| 卷号 | 1003期号:1 |
| ISSN号 | 0004-637X |
| DOI | 10.3847/1538-4357/ae63b4 |
| 产权排序 | 第6完成单位 |
| 文献子类 | Article |
| 英文摘要 | When a radio jet is partially optically thick in the launching region, its apparent compact core may display frequency-dependent positional shifts. High-precision astrometric measurements of core shifts enable astronomers to pinpoint the jet's origin and place tight constraints on the magnetic field. BL Lacertae, the archetypal BL Lac object, hosts a highly variable and well-collimated jet. To independently constrain its innermost core shifts, we conducted very long baseline interferometric (VLBI) observations at 8.4, 12.4, 15.2, 23.6, and 43.2 GHz. By exploiting a nearby (13.' 3) steep-spectrum calibrator (NVSS J220340+420839) through inverse phase-referencing VLBI astrometry, we detect nearly unbiased two-dimensional core shift measurements with state-of-the-art precisions of 5-30 mu as, which are significant at >3 sigma confidence. The core shift between 8.4 and 43.2 GHz reaches 250 mu as. The apparent core shifts scale with frequency as nu-1/k(r), implying the existence of an optically thick region in the upstream of the jet. The derived core-shift index, k(r)=1.18(-0.34)(+0.59), is consistent, within uncertainties, with the canonical k(r) = 1 expected under energy equipartition between the jet particle and magnetic field energy densities, while allowing for modest deviations given that BL Lacertae was captured in a flaring state. |
| 学科主题 | 天文学 ; 射电天文学 |
| URL标识 | 查看原文 |
| 出版地 | No.2 The Distillery, Glassfields, Avon Street, Bristol, ENGLAND |
| WOS关键词 | ACTIVE GALACTIC NUCLEI ; AGN JETS ; RELATIVISTIC JETS ; MAGNETIC-FIELDS ; ASTROPY ; PACKAGE ; PROJECT ; RAY |
| 资助项目 | National Research Foundation of Korea (NRF)[RS-2024-00407499]; MOST divided by National Natural Science Foundation of China (NSFC)[12573070] |
| WOS研究方向 | Astronomy & Astrophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:001765367700001 |
| 出版者 | IOP Publishing Ltd |
| 资助机构 | National Research Foundation of Korea (NRF)[RS-2024-00407499] ; MOST divided by National Natural Science Foundation of China (NSFC)[12573070] |
| 版本 | 出版稿 |
| 源URL | [http://ir.ynao.ac.cn/handle/114a53/29228]  |
| 专题 | 云南天文台_射电天文研究组 |
| 通讯作者 | Liu, Niu |
| 作者单位 | 1.School of Astronomy and Space Science, Nanjing University, Nanjing 210023, People’s Republic of China; niu.liu@nju.edu.cn; 2.Key Laboratory of Modern Astronomy and Astrophysics (Ministry of Education), Nanjing University, Nanjing 210023, People’s Republic of China; 3.Department of Physics and Astronomy, Chalmers University of Technology, Onsala Space Observatory, SE-43992 Onsala, Sweden; jun.yang@chalmers.se; 4.Korea Astronomy and Space Science Institute, 776 Daedeok-daero, Yuseong-gu, Daejeon 34055, Republic of Korea; xcheng@kasi.re.kr; 5.Instituto de Astrofísica de Andalucía-CSIC, Glorieta de la Astronomía s/n, E-18008 Granada, Spain; 6.Yunnan Observatories, Chinese Academy of Sciences, Yangfangwang 396th, Kunming, People’s Republic of China; 7.Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, People’s Republic of China; 8.University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China; 9.University of Chinese Academy of Sciences, Nanjing 211135, People’s Republic of China |
| 推荐引用方式 GB/T 7714 | Liu, Niu,Yang, Jun,Cheng, Xiaopeng,et al. Detections of Nearly Bias-free Core Shifts with 5-30 μas Precisions at 8-43 GHz in BL Lacertae[J]. ASTROPHYSICAL JOURNAL,2026,1003(1). |
| APA | Liu, Niu.,Yang, Jun.,Cheng, Xiaopeng.,Zeng, Ai-Ling.,陈文.,...&Zhu, Zi.(2026).Detections of Nearly Bias-free Core Shifts with 5-30 μas Precisions at 8-43 GHz in BL Lacertae.ASTROPHYSICAL JOURNAL,1003(1). |
| MLA | Liu, Niu,et al."Detections of Nearly Bias-free Core Shifts with 5-30 μas Precisions at 8-43 GHz in BL Lacertae".ASTROPHYSICAL JOURNAL 1003.1(2026). |
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来源：云南天文台
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