East Asian VLBI Network Observations of Active Galactic Nuclei Jets: Imaging with KaVA+Tianma+Nanshan

• Published in: arXiv.org 2021-04
• Main Authors: Cui, Yuzhu, Hada, Kazuhiro, Kino, Motoki, Sohn, Bong Won, Park, Jongho, Ro, Hyun Wook, Sawada-Satoh, Satoko, Wu, Jiang, Lang, Cui, Honma, Mareki, Shen, Zhi Qiang, Tazaki, Fumie, An, Tao, Cho, Ilje, Guang Yao Zhao, Xiao Peng Cheng, Niinuma, Kotaro, Wajima, Kiyoaki, Ying Kang Zhang, Kawaguchi, Noriyuki, Algaba, Juan Carlos, Koyama, Shoko, Hirota, Tomoya, Yonekura, Yoshinori, Sakai, Nobuyuki, Xia, Bo, Yong Bin Jiang, Lin Feng Yu, Gou, Wei, Hwang, Ju Yeon, Yong Chen Jiang, Yun Xia Sun, Jung, Dong Kyu, Kim, Hyo Ryoung, Kim, Jeong Sook, Kobayashi, Hideyuki, Lee, Jee Won, Lee, Jeong Ae, Zhang, Hua, Guang Hui Li, Xu, Zhi Qiang, Li, Peng, Oh, Jung Hwan, Se Jin Oh, Oh, Chung Sik, Oyama, Tomoaki, Roh, Duk Gyoo, Shibata, Katsunori M, Guo, Wen, Zhao, Rong Bing, Wei Ye Zhong, Wang, Jin Qing, Yang, Wen Jun, Yan, Hao, Yeom, Jae Hwan, Li, Bin, Li, Xiao Fei, Yuan, Jian Ping, Dong, Jian, Chen, Zhong, Akiyama, Kazunori, Asada, Keiichi, Do Young Byun, Hagiwara, Yoshiaki, Hodgson, Jeffrey, Jung, Tae Hyun, Kim, Kee Tae, Sang Sung Lee, Kunwoo Yi, Qing Hui Liu, Liu, Xiang, Ru Sen Lu, Nakamura, Masanori, Trippe, Sascha, Wang, Na, Xue Zheng Wang, Zhang, Bo
• Format: Article
• Language: English
• Subjects: Active galactic nuclei; Angular resolution; Arrays; Astrometry; Image resolution; Morphology; Radio telescopes; Sensitivity; Telescopes; Very long base interferometry
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2104.05525

The East Asian very-long-baseline interferometry (VLBI) Network (EAVN) is a rapidly evolving international VLBI array that is currently promoted under joint efforts among China, Japan, and Korea. EAVN aims at forming a joint VLBI Network by combining a large number of radio telescopes distributed over East Asian regions. After the combination of the Korean VLBI Network (KVN) and the VLBI Exploration of Radio Astrometry (VERA) into KaVA, further expansion with the joint array in East Asia is actively promoted. Here we report the first imaging results (at 22 and 43 GHz) of bright radio sources obtained with KaVA connected to Tianma 65-m and Nanshan 26-m Radio Telescopes in China. To test the EAVN imaging performance for different sources, we observed four active galactic nuclei (AGN) having different brightness and morphology. As a result, we confirmed that Tianma 65-m Radio Telescope (TMRT) significantly enhances the overall array sensitivity, a factor of 4 improvement in baseline sensitivity and 2 in image dynamic range compared to the case of KaVA only. The addition of Nanshan 26-m Radio Telescope (NSRT) further doubled the east-west angular resolution. With the resulting high-dynamic-range, high-resolution images with EAVN (KaVA+TMRT+NSRT), various fine-scale structures in our targets, such as the counter-jet in M87, a kink-like morphology of the 3C273 jet and the weak emission in other sources, are successfully detected. This demonstrates the powerful capability of EAVN to study AGN jets and to achieve other science goals in general. Ongoing expansion of EAVN will further enhance the angular resolution, detection sensitivity and frequency coverage of the network.