Hyo-Ryoung Kim — Scifaro

A Geodetic and Astrometric VLBI Experiment at 22/43/88/132 GHz

Extending geodetic and astrometric Very Long Baseline Interferometry (VLBI) observations from traditional centimeter wavebands to millimeter wavebands offers numerous scientific potentials and benefits. However, it was considered quite…

Instrumentation and Methods for Astrophysics · Physics 2024-09-12 Shuangjing Xu , Taehyun Jung , Bo Zhang , Ming Hui Xu , Do-Young Byun , Xuan He , Nobuyuki Sakai , Oleg Titov , Fengchun Shu , Hyo-Ryoung Kim , Jungho Cho , Sung-Moon Yoo , Byung-Kyu Choi , Woo Kyoung Lee , Yan Sun , Xiaofeng Mai , Guangli Wang

Precessing jet nozzle connecting to a spinning black hole in M87

The nearby radio galaxy M87 offers a unique opportunity to explore the connections between the central supermassive black hole and relativistic jets. Previous studies of the inner region of M87 revealed a wide opening angle for the jet…

High Energy Astrophysical Phenomena · Physics 2023-10-16 Yuzhu Cui , Kazuhiro Hada , Tomohisa Kawashima , Motoki Kino , Weikang Lin , Yosuke Mizuno , Hyunwook Ro , Mareki Honma , Kunwoo Yi , Jintao Yu , Jongho Park , Wu Jiang , Zhiqiang Shen , Evgeniya Kravchenko , Juan-Carlos Algaba , Xiaopeng Cheng , Ilje Cho , Gabriele Giovannini , Marcello Giroletti , Taehyun Jung , Ru-Sen Lu , Kotaro Niinuma , Junghwan Oh , Ken Ohsuga , Satoko Sawada-Satoh , Bong Won Sohn , Hiroyuki R. Takahashi , Mieko Takamura , Fumie Tazaki , Sascha Trippe , Kiyoaki Wajima , Kazunori Akiyama , Tao An , Keiichi Asada , Salvatore Buttaccio , Do-Young Byun , Lang Cui , Yoshiaki Hagiwara , Tomoya Hirota , Jeffrey Hodgson , Noriyuki Kawaguchi , Jae-Young Kim , Sang-Sung Lee , Jee Won Lee , Jeong Ae Lee , Giuseppe Maccaferri , Andrea Melis , Alexey Melnikov , Carlo Migoni , Se-Jin Oh , Koichiro Sugiyama , Xuezheng Wang , Yingkang Zhang , Zhong Chen , Ju-Yeon Hwang , Dong-Kyu Jung , Hyo-Ryoung Kim , Jeong-Sook Kim , Hideyuki Kobayashi , Bin Li , Guanghui Li , Xiaofei Li , Zhiyong Liu , Qinghui Liu , Xiang Liu , Chung-Sik Oh , Tomoaki Oyama , Duk-Gyoo Roh , Jinqing Wang , Na Wang , Shiqiang Wang , Bo Xia , Hao Yan , Jae-Hwan Yeom , Yoshinori Yonekura , Jianping Yuan , Hua Zhang , Rongbing Zhao , Weiye Zhong

Spectral analysis of a parsec-scale jet in M87: Observational constraint on the magnetic field strengths in the jet

Because of its proximity and the large size of its black hole, M87 is one of the best targets for studying the launching mechanism of active galactic nucleus jets. Currently, magnetic fields are considered to be an essential factor in the…

High Energy Astrophysical Phenomena · Physics 2023-05-24 Hyunwook Ro , Motoki Kino , Bong Won Sohn , Kazuhiro Hada , Jongho Park , Masanori Nakamura , Yuzhu Cui , Kunwoo Yi , Aeree Chung , Jeffrey Hodgson , Tomohisa Kawashima , Tao An , Sascha Trippe , Juan-Carlos Algaba , Jae-Young Kim , Satoko Sawada-Satoh , Kiyoaki Wajima , Zhiqiang Shen , Xiaopeng Cheng , Ilje Cho , Wu Jiang , Taehyun Jung , Jee-Won Lee , Kotaro Niinuma , Junghwan Oh , Fumie Tazaki , Guang-Yao Zhao , Kazunori Akiyama , Mareki Honma , Jeong Ae Lee , Rusen Lu , Yingkang Zhang , Keiichi Asada , Lang Cui , Yoshiaki Hagiwara , Tomoya Hirota , Noriyuki Kawaguchi , Shoko Koyama , Sang-Sung Lee , Se-Jin Oh , Koichiro Sugiyama , Mieko Takamura , Xuezheng Wang , Ju-Yeon Hwang , Dong-Kyu Jung , Hyo-Ryoung Kim , Jeong-Sook Kim , Hideyuki Kobayashi , Chung-Sik Oh , Tomoaki Oyama , Duk-Gyoo Roh , Jae-Hwan Yeom

Overview of the Observing System and Initial Scientific Accomplishments of the East Asian VLBI Network (EAVN)

The East Asian VLBI Network (EAVN) is an international VLBI facility in East Asia and is operated under mutual collaboration between East Asian countries, as well as part of Southeast Asian and European countries. EAVN currently consists of…

Instrumentation and Methods for Astrophysics · Physics 2022-12-15 Kazunori Akiyama , Juan-Carlos Algaba , Tao An , Keiichi Asada , Kitiyanee Asanok , Do-Young Byun , Thanapol Chanapote , Wen Chen , Zhong Chen , Xiaopeng Cheng , James O. Chibueze , Ilje Cho , Se-Hyung Cho , Hyun-Soo Chung , Lang Cui , Yuzhu Cui , Akihiro Doi , Jian Dong , Kenta Fujisawa , Wei Gou , Wen Guo , Kazuhiro Hada , Yoshiaki Hagiwara , Tomoya Hirota , Jeffrey A. Hodgson , Mareki Honma , Hiroshi Imai , Phrudth Jaroenjittichai , Wu Jiang , Yongbin Jiang , Yongchen Jiang , Takaaki Jike , Dong-Kyu Jung , Taehyun Jung , Noriyuki Kawaguchi , Dong-Jin Kim , Hyo-Ryoung Kim , Jaeheon Kim , Jeong-Sook Kim , Kee-Tae Kim , Soon-Wook Kim , Motoki Kino , Hideyuki Kobayashi , Shoko Koyama , Busaba H. Kramer , Jee-Won Lee , Jeong Ae Lee , Sang-Sung Lee , Sang Won Lee , Bin Li , Guanghui Li , Xiaofei Li , Zhixuan Li , Qinghui Liu , Xiang Liu , Ru-Sen Lu , Kazuhito Motogi , Masanori Nakamura , Kotaro Niinuma , Chungsik Oh , Hongjong Oh , Junghwan Oh , Se-Jin Oh , Tomoaki Oyama , Jongho Park , Saran Poshyachinda , Hyunwook Ro , Duk-Gyoo Roh , Wiphu Rujopakarn , Nobuyuki Sakai , Satoko Sawada-Satoh , Zhi-Qiang Shen , Katsunori M. Shibata , Bong Won Sohn , Boonrucksar Soonthornthum , Koichiro Sugiyama , Yunxia Sun , Mieko Takamura , Yoshihiro Tanabe , Fumie Tazaki , Sascha Trippe , Kiyoaki Wajima , Jinqing Wang , Na Wang , Shiqiang Wang , Xuezheng Wang , Bo Xia , Shuangjing Xu , Hao Yan , Wenjun Yang , Jae-Hwan Yeom , Kunwoo Yi , Sang-Oh Yi , Yoshinori Yonekura , Hasu Yoon , Linfeng Yu , Jianping Yuan , Youngjoo Yun , Bo Zhang , Hua Zhang , Yingkang Zhang , Guang-Yao Zhao , Rongbing Zhao , Weiye Zhong

The intrinsic structure of Sagittarius A* at 1.3 cm and 7 mm

Sagittarius A* (Sgr A*), the Galactic Center supermassive black hole (SMBH), is one of the best targets to resolve the innermost region of SMBH with very long baseline interferometry (VLBI). In this study, we have carried out observations…

High Energy Astrophysical Phenomena · Physics 2022-04-06 Ilje Cho , Guang-Yao Zhao , Tomohisa Kawashima , Motoki Kino , Kazunori Akiyama , Michael D. Johnson , Sara Issaoun , Kotaro Moriyama , Xiaopeng Cheng , Juan-Carlos Algaba , Taehyun Jung , Bong Won Sohn , Thomas P. Krichbaum , Maciek Wielgus , Kazuhiro Hada , Ru-Sen Lu , Yuzhu Cui , Satoko Sawada-Satoh , Zhiqiang Shen , Jongho Park , Wu Jiang , Hyunwook Ro , Kunwoo Yi , Kiyoaki Wajima , Jee Won Lee , Jeffrey Hodgson , Fumie Tazaki , Mareki Honma , Kotaro Niinuma , Sascha Trippe , Tao An , Yingkang Zhang , Jeong Ae Lee , Se-Jin Oh , Do-Young Byun , Sang-Sung Lee , Jae-Young Kim , Junghwan Oh , Shoko Koyama , Keiichi Asada , Xuezheng Wang , Lang Cui , Yoshiaki Hagiwara , Masanori Nakamura , Mieko Takamura , Tomoya Hirota , Koichiro Sugiyama , Noriyuki Kawaguchi , Hideyuki Kobayashi , Tomoaki Oyama , Yoshinori Yonekura , Jongsoo Kim , Ju-Yeon Hwang , Dong-Kyu Jung , Hyo-Ryoung Kim , Jeong-Sook Kim , Chung-Sik Oh , Duk-Gyoo Roh , Jae-Hwan Yeom , Bo Xia , Weiye Zhong , Bin Li , Rongbing Zhao , Jinqing Wang , Qinghui Liu , Zhong Chen

Kinematics of the M87 jet in the collimation zone: gradual acceleration and velocity stratification

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…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Jongho Park , Kazuhiro Hada , Motoki Kino , Masanori Nakamura , Jeffrey Hodgson , Hyunwook Ro , Yuzhu Cui , Keiichi Asada , Juan-Carlos Algaba , Satoko Sawada-Satoh , Sang-Sung Lee , Ilje Cho , Zhiqiang Shen , Wu Jiang , Sascha Trippe , Kotaro Niinuma , Bong Won Sohn , Taehyun Jung , Guang-Yao Zhao , Kiyoaki Wajima , Fumie Tazaki , Mareki Honma , Tao An , Kazunori Akiyama , Do-Young Byun , Jongsoo Kim , Yingkang Zhang , Xiaopeng Cheng , Hideyuki Kobayashi , Katsunori M. Shibata , Jee Won Lee , Duk-Gyoo Roh , Se-Jin Oh , Jae-Hwan Yeom , Dong-Kyu Jung , Chungsik Oh , Hyo-Ryoung Kim , Ju-Yeon Hwang , Yoshiaki Hagiwara

Jet Kinematics of the Quasar 4C +21.35 from Observations with the KaVA Very Long Baseline Interferometry Array

We present the jet kinematics of the flat spectrum radio quasar (FSRQ) 4C +21.35 using time-resolved KaVA very long baseline interferometry array radio maps obtained from September 2014 to July 2016. During two out of three observing…

Astrophysics of Galaxies · Physics 2019-04-17 Taeseok Lee , Sascha Trippe , Motoki Kino , Bong Won Sohn , Jongho Park , Junghwan Oh , Kazuhiro Hada , Kotaro Niinuma , Hyunwook Ro , Taehyun Jung , Guang-Yao Zhao , Sang-Sung Lee , Juan-Carlos Algaba , Kazunori Akiyama , Kiyoaki Wajima , Satoko Sawada-Satoh , Fumie Tazaki , Ilje Cho , Jeffrey Hodgson , Jeong Ae Lee , Yoshiaki Hagiwara , Mareki Honma , Shoko Koyama , Tao An , Yuzhu Cui , Hyemin Yoo , Noriyuki Kawaguchi , Duk-Gyoo Roh , Se-Jin Oh , Jae-Hwan Yeom , Dong-Kyu Jung , Chungsik Oh , Hyo-Ryoung Kim , Ju-Yeon Hwang , Do-Young Byun , Se-Hyung Cho , Hyun-Goo Kim , Hideyuki Kobayashi , Katsunori M. Shibata , Zhiqiang Shen , Wu Jiang , Jee Won Lee

A broad HCO+ absorption line associated with the circumnuclear torus of NGC 1052

In the circumnuclear region of the nearby radio galaxy NGC~1052. Our $\lambda$3mm VLBI observations with the Korean VLBI Network have spatially resolved the broad HCO$^{+}$ absorption at a velocity range of 1350--1850 km~s$^{-1}$ against a…

Astrophysics of Galaxies · Physics 2019-03-06 Satoko Sawada-Satoh , Do-Young Byun , Sang-Sung Lee , Se-Jin Oh , Duk-Gyoo Roh , Seiji Kameno , Jae-Hwan Yeom , Dong-Kyu Jung , Chungsik Oh , Hyo-Ryoung Kim , Ju-Yeon Hwang

Pilot KaVA monitoring on the M87 jet: confirming the inner jet structure and superluminal motions at sub-pc scales

We report the initial results of our high-cadence monitoring program on the radio jet in the active galaxy M87, obtained by the KVN and VERA Array (KaVA) at 22 GHz. This is a pilot study that preceded a larger KaVA-M87 monitoring program,…

High Energy Astrophysical Phenomena · Physics 2017-09-20 Kazuhiro Hada , Jong Ho Park , Motoki Kino , Kotaro Niinuma , Bong Won Sohn , Hyun Wook Ro , Taehyun Jung , Juan-Carlos Algaba , Guang-Yao Zhao , Sang-Sung Lee , Kazunori Akiyama , Sascha Trippe , Kiyoaki Wajima , Satoko Sawada-Satoh , Fumie Tazaki , Ilje Cho , Jeffrey Hodgson , Jeong Ae Lee , Yoshiaki Hagiwara , Mareki Honma , Shoko Koyama , Junghwan Oh , Taeseak Lee , Hyemin Yoo , Noriyuki Kawaguchi , Duk-Gyoo Roh , Se-Jin Oh , Jae-Hwan Yeom , Dong-Kyu Jung , Chungsik Oh , Hyo-Ryoung Kim , Ju-Yeon Hwang , Do-Young Byun , Se-Hyung Cho , Hyun-Goo Kim , Hideyuki Kobayashi , Katsunori M. Shibata

Spatially Resolved HCN Absorption Features in the Circumnuclear Region of NGC 1052

We present the first VLBI detection of HCN molecular absorption in the nearby active galactic nucleus NGC 1052. Utilizing the 1 milliarcsecond resolution achieved by the Korean VLBI Network, we have spatially resolved the HCN absorption…

Astrophysics of Galaxies · Physics 2016-10-12 Satoko Sawada-Satoh , Duk-Gyoo Roh , Se-Jin Oh , Sang-Sung Lee , Do-Young Byun , Seiji Kameno , Jae-Hwan Yeom , Dong-Kyu Jung , Hyo-Ryoung Kim , Ju-Yeon Hwang

Astrometrically Registered Simultaneous Observations of the 22 GHz H$_2$O and the 43GHz SiO masers towards R Leonis Minoris using KVN and Source/Frequency Phase Referencing

Oxygen-rich Asymptotic Giant Branch (AGB) stars can be intense emitters of SiO ($v$=1 and 2, J=1$\rightarrow$0) and H$_2$O maser lines at 43 and 22 GHz, respectively. VLBI observations of the maser emission provide a unique tool to probe…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Richard Dodson , María J. Rioja , Tae-Hyun Jung , Bong-Won Sohn , Do-Young Byun , Se-Hyung Cho , Sang-Sung Lee , Jongsoo Kim , Kee-Tae Kim , Chung-Sik Oh , Seog-Tae Han , Do-Heung Je , Moon-Hee Chung , Seog-Oh Wi , Jiman Kang , Jung-Won Lee , Hyunsoo Chung , Hyo-Ryoung Kim , Hyun-Goo Kim , Chang-Hoon Lee , Duk-Gyoo Roh , Se-Jin Oh , Jae-Hwan Yeom , Min-Gyu Song , Yong-Woo Kang