45 citations · 476 across the 38 of their papers we have counts for
40 papers
Cosmological Distance Measurements of High Redshift Blazars: OJ 248 (z=0.939) and 4C +38.41 (z=1.814)
Young-Bin Shin, Sang-Sung Lee, Sincheol Kang +3
In this study, we estimated the angular diameter distances to two high-redshift active galactic nuclei (AGNs), OJ 248 (z = 0.939) and 4C +38.41 (z = 1.814), using 43 GHz radio ligh…
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…
Where within the 3C 84 jet are -rays produced?
Georgios F. Paraschos, Ioannis Liodakis, Svetlana Jorstad +49
The location of -ray creation and emission within extra-galactic jets is a matter of active debate. One particularly well-suited source to pinpoint the location is the nearby, b…
A distance measurement for blazar TXS 0506+056 using its radio variability and very long baseline images
Chanwoo Song, Sang-Sung Lee, Sincheol Kang +1
We present the results of constraining the angular diameter distance to blazar TXS 0506+056. We used data obtained with the 15 GHz VLBA in MJD 54838-60262 and data from the 15 GHz…
Detection of Compton scattering in the jet of 3C 84
Ioannis Liodakis, Sudip Chakraborty, Frédéric Marin +77
3C 84 is the brightest cluster galaxy in the Perseus Cluster. It is among the closest radio-loud active galaxies and among the very few that can be detected from low frequency radi…
The variability angular diameter distance and the intrinsic brightness temperature of active galactic nuclei
Whee Yeon Cheong, Sang-Sung Lee, Chanwoo Song +5
Context. It has recently been suggested that angular diameter distances derived from comparing the variability timescales of blazars to angular size measurements with very long bas…
Unveiling blazar synchrotron emission: a multiwavelength polarimetric study of HSP and LSP populations
Sara Capecchiacci, Ioannis Liodakis, Riccardo Middei +96
Polarimetric properties of blazars allow us to put constraints on the acceleration mechanisms that fuel their powerful jets. By studying the multiwavelength polarimetric behaviour…
Determining the origin of the X-ray emission in blazars through multiwavelength polarization
Ioannis Liodakis, Haocheng Zhang, Stella Boula +48
The origin of the high-energy emission in astrophysical jets from black holes is a highly debated issue. This is particularly true for jets from supermassive black holes that are a…
High optical to X-ray polarization ratio reveals Compton scattering in BL Lacertae's jet
Ivan Agudo, Ioannis Liodakis, Jorge Otero-Santos +147
Blazars, supermassive black hole systems (SMBHs) with highly relativistic jets aligned with the line of sight, are the most powerful long-lived emitters of electromagnetic emission…
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…
A Two-Week Monitoring Campaign on Mrk 421
W. Peter Maksym, Ioannis Liodakis, M. Lynne Saade +153
X-ray polarization is a unique new probe of the particle acceleration in astrophysical jets made possible through the Imaging X-ray Polarimetry Explorer. Here we report on the firs…
X-ray and multiwavelength polarization of Mrk 501 from 2022 to 2023
Chien-Ting J. Chen, Ioannis Liodakis, Riccardo Middei +143
We present multiwavelength polarization measurements of the luminous blazar Mrk~501 over a 14-month period. The 2--8 keV X-ray polarization was measured with the Imaging X-ray Pola…
IXPE observation of PKS 2155-304 reveals the most highly polarized blazar
Pouya M. Kouch, Ioannis Liodakis, Riccardo Middei +133
We report the X-ray polarization properties of the high-synchrotron-peaked (HSP) blazar PKS 2155304 based on observations with the Imaging X-ray Polarimetry Explorer (IXPE). We…
A study of the radio spectrum of Mrk 421
Jee Won Lee, Sang-Sung Lee, Jeffrey Hodgson +5
We present the results of a spectral analysis using simultaneous multifrequency (22, 43, 86, and 129 GHz) very long baseline interferometry (VLBI) observations of the Korean VLBI N…
A Near Magnetic-to-kinetic Energy Equipartition Flare from the Relativistic Jet in AO 0235+164 during 2013-2019
Whee Yeon Cheong, Sang-Sung Lee, Sang-Hyun Kim +17
We present the multiwavelength flaring activity of the blazar AO 0235+164 during its recent active period from 2013 to 2019. From a discrete correlation function (DCF) analysis, we…
Observations of Low and Intermediate Spectral Peak Blazars with the Imaging X-ray Polarimetry Explorer
Herman L. Marshall, Ioannis Liodakis, Alan P. Marscher +145
We present X-ray polarimetry observations from the Imaging X-ray Polarimetry Explorer (IXPE) of three low spectral peak and one intermediate spectral peak blazars, namely 3C 273, 3…
Magnetic Field Properties inside the Jet of Mrk 421: Multiwavelength Polarimetry Including the Imaging X-ray Polarimetry Explorer
Dawoon E. Kim, Laura Di Gesu, Ioannis Liodakis +133
We conducted a polarimetry campaign from radio to X-ray wavelengths of the high-synchrotron-peak (HSP) blazar Mrk 421, including Imaging X-ray Polarimetry Explorer (IXPE) measureme…
IXPE and multi-wavelength observations of blazar PG 1553+113 reveal an orphan optical polarization swing
Riccardo Middei, Matteo Perri, Simonetta Puccetti +119
The lower energy peak of the spectral energy distribution of blazars has commonly been ascribed to synchrotron radiation from relativistic particles in the jets. Despite the consen…
Double SSA Spectrum and Magnetic Field Strength of the FSRQ 3C 454.3
Hyeon-Woo Jeong, Sang-Sung Lee, Whee Yeon Cheong +7
We present the results of a radio multi-frequency () study of the blazar 3C~454.3. After subtracting the quiescent spectrum corresponding to optically thin emission,…
X-ray Polarization of BL Lacertae in Outburst
Abel L. Peirson, Michela Negro, Ioannis Liodakis +128
We report the first confidence detection of X-ray polarization in BL Lacertae. During a recent X-ray/-ray outburst, a 287 ksec observation (2022 November 27-30) was tak…
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…
Magnetic Field Strengths of the Synchrotron Self-Absorption Region in the Jet of CTA 102 During Radio Flares
Sang-Hyun Kim, Sang-Sung Lee, Jee Won Lee +15
CTA 102 is a blazar implying that its relativistic jet points towards Earth and emits synchrotron radiation produced by energetic particles gyrating in the magnetic field. This stu…
Interferometric Monitoring of Gamma-ray Bright AGNs: OJ 287
Jee Won Lee, Sang-Sung Lee, Juan-Carlos Algaba +9
We present the results of simultaneous multi-frequency imaging observations at 22, 43, 86, and 129\,GHz of OJ\,287. We used the Korean VLBI Network as part of the Interferometric M…
Origin and Evolution of the Multi-band Variability in the Flat Spectrum Radio Source 4C 38.41
Juan Carlos Algaba, Sang Sung Lee, Bindu Rani +13
The flat spectrum radio quasar 4C 38.41 showed a significant increase of its radio flux density during the period 2012 March - 2015 August which correlates with gamma-ray flaring a…