28 citations · 83 across the 11 of their papers we have counts for
13 papers
The 2015-2017 Large EVPA Rotation in OJ 287: Dominant Propagating Component in a Helical Magnetic Field with Time-Dependent Viewing Geometry
Wanchaloem Khwammai, Minchul Kam, Motoki Kino +11
We present high-cadence, multi-frequency monitoring of the blazar OJ 287 using KVN (22--129 GHz), ALMA (91.5--343.5 GHz), and Metsähovi (37 GHz), covering 2012--2023, together with…
Verification of the Polarimetric Capability of the East Asia VLBI Network
Yunjeong Lee, Jongho Park, Do-Young Byun +10
The East Asia VLBI Network (EAVN) has recently enabled dual-polarization observations at and . We present the first systematic verification of its polarimetr…
A Unified Origin of Faraday Rotation toward 3C 84: The Circumnuclear Ambient Medium within the Parsec-Scale Bondi Radius of the Host Galaxy NGC 1275
Minchul Kam, Jongho Park, Sascha Trippe +11
We present multi-frequency polarimetric observations of 3C 84 obtained with the Korean VLBI Network at 43-141 GHz, the Very Long Baseline Array at 43 GHz, and the High Sensitivity…
Helical Magnetic Field in the Acceleration--Collimation Zone of the M87 Jet
Jongho Park, Kazuya Takahashi, Kenji Toma +10
Relativistic jets from supermassive black holes are expected to be magnetically launched and guided, with magnetic energy systematically converted to bulk kinetic energy throughout…
Monitoring of 3C 286 with ALMA, IRAM, and SMA from 2006 to 2025: Stability, Synchrotron Ages, and Frequency-Dependent Polarization Attributed to Core-Shift
Minchul Kam, Hiroshi Nagai, Motoki Kino +23
We present the results of multi-frequency monitoring of the radio quasar 3C 286, conducted using three instruments: ALMA at 91.5, 103.5, 233.0, and 343.4 GHz, the IRAM 30-m Telesco…
Polarization flare of 3C 454.3 in millimeter wavelengths seen from decadal polarimetric observations
Hyeon-Woo Jeong, Sang-Sung Lee, Sincheol Kang +6
This study investigates polarimetric characteristics of the blazar 3C~454.3 at 22-129~GHz using decadal~(2011-2022) data sets. In addition, we also delve into the origin of the pol…
Discovery of Limb Brightening in the Parsec-scale Jet of NGC 315 through Global Very Long Baseline Interferometry Observations and Its Implications for Jet Models
Jongho Park, Guang-Yao Zhao, Masanori Nakamura +19
We report the first observation of the nearby giant radio galaxy NGC 315 using a global VLBI array consisting of 22 radio antennas located across five continents, including high-se…
Observational Evidence to Support a Dense Ambient Medium Shaping the Jet in 3C 84
Jongho Park, Motoki Kino, Hiroshi Nagai +4
Highly collimated relativistic jets are a defining feature of certain active galactic nuclei (AGN), yet their formation mechanism remains elusive. Previous observations and theoret…
Evolution of the Termination Region of the Parsec-Scale Jet of 3C 84 Over the Past 20 Years
Minchul Kam, Jeffrey A. Hodgson, Jongho Park +4
We present the kinematics of the parsec-scale jet in 3C 84 from 2003 November to 2022 June observed with the Very Long Baseline Array (VLBA) at 43 GHz. We find that the C3 componen…
Probing the Heart of Active Narrow-line Seyfert 1 Galaxies with VERA Wideband Polarimetry
Mieko Takamura, Kazuhiro Hada, Mareki Honma +9
We explored the parsec-scale nuclear regions of a sample of radio-loud narrow-line Seyfert 1 galaxies (NLSy1s) using the VLBI Exploration of Radio Astronomy (VERA) wideband (at a r…
Using the Crab Nebula as Polarization Angle Calibrator for the Korean VLBI Network
Minchul Kam, Sascha Trippe, Do-Young Byun +5
The Crab nebula is widely used as a polarization angle calibrator for single-dish radio observations because of its brightness, high degree of linear polarization, and well-known p…
A persistent double nuclear structure in 3C 84
Junghwan Oh, Jeffrey A. Hodgson, Sascha Trippe +11
3C 84 (NGC 1275) is the radio source at the center of the Perseus Cluster and exhibits a bright radio jet. We observed the source with the Global Millimeter VLBI Array (GMVA) betwe…
Revealing the Nature of Blazar Radio Cores through Multi-Frequency Polarization Observations with the Korean VLBI Network
Jongho Park, Minchul Kam, Sascha Trippe +13
We study the linear polarization of the radio cores of eight blazars simultaneously at 22, 43, and 86 GHz with observations obtained by the Korean VLBI Network (KVN) in three epoch…