252 citations · 2.8k across the 102 of their papers we have counts for
19 papers · 1 filter
First characterization of the emission behavior of Mrk421 from radio to VHE gamma rays with simultaneous X-ray polarization measurements
S. Abe, J. Abhir, V. A. Acciari +250
We perform the first broadband study of Mrk421 from radio to TeV gamma rays with simultaneous measurements of the X-ray polarization from IXPE. The data were collected within an ex…
Unprecedented extreme high-frequency radio variability in early-stage active galactic nuclei
E. Järvelä, T. Savolainen, M. Berton +9
We report on the discovery of one of the most extreme cases of high-frequency radio variability ever measured in active galactic nuclei (AGN), observed on timescales of days and ex…
Zero-polarization candidate regions for calibration of wide-field optical polarimeters
N. Mandarakas, G. V. Panopoulou, V. Pelgrims +14
Context. Calibration of optical polarimeters relies on the use of stars with negligible polarization (unpolarized standard stars) for determining the instrumental polarization zero…
Multi-wavelength observations of the lensed quasar PKS 1830211 during the 2019 -ray flare
S. Vercellone, I. Donnarumma, C. Pittori +32
PKS 1830211 is a -ray emitting, high-redshift (z ), lensed flat-spectrum radio quasar. During the period mid-February to mid-April 2019, this source underw…
Optical circular polarization of blazar S4 0954+65 during high linear polarized states
I. Liodakis, E. Shablovinskaya, D. Blinov +17
Optical circular polarization observations can directly test the particle composition in black holes jets. Here we report on the first observations of the BL Lac type object S4 095…
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…
Extreme photometric and polarimetric variability of blazar S4 0954+65 at its maximum optical and -ray brightness levels
C. M. Raiteri, M. Villata, M. I. Carnerero +64
In 2022 the BL Lac object S4 0954+65 underwent a major variability phase, reaching its historical maximum brightness in the optical and -ray bands. We present optical photometri…
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…
Multi-year characterisation of the broad-band emission from the intermittent extreme BL Lac 1ES~2344+514
H. Abe, S. Abe, V. A. Acciari +232
The BL Lac 1ES 2344+514 is known for temporary extreme properties (e.g., a shift of the synchrotron SED peak energy above 1keV). While those extreme states were so fa…
Searches for neutrinos in the direction of radio-bright blazars with the ANTARES telescope
ANTARES Collaboration, A. Albert, S. Alves +162
Active galaxies, especially blazars, are among the most promising neutrino source candidates. To date, ANTARES searches for these objects considered GeV-TeV -ray bright blazars.…
Milliarcsecond Core Size Dependence of the Radio Variability of Blazars
Po Chih Hsu, Jun Yi Koay, Satoki Matsushita +6
Studying the long-term radio variability (timescales of months to years) of blazars enables us to gain a better understanding of the physical structure of these objects on sub-pars…
Multiple imaging of the quasar 2005+403 formed by anisotropic scattering
T. A. Koryukova, A. B. Pushkarev, S. Kiehlmann +1
We report on the low Galactic latitude () quasar 2005403, the second active galactic nuclei, in which we detected a rare phenomenon of multiple imaging induced by r…
The RoboPol sample of optical polarimetric standards
D. Blinov, S. Maharana, F. Bouzelou +34
Optical polarimeters are typically calibrated using measurements of stars with known and stable polarization parameters. However, there is a lack of such stars available across the…
Discovery of X-ray polarization angle rotation in active galaxy Mrk 421
Laura Di Gesu, Herman L. Marshall, Steven R. Ehlert +140
The magnetic field conditions in astrophysical relativistic jets can be probed by multiwavelength polarimetry, which has been recently extended to X-rays. For example, one can trac…
Bright-Moon Sky as a Wide-Field Linear Polarimetric Flat Source for Calibration
S. Maharana, S. Kiehlmann, D. Blinov +20
Next-generation wide-field optical polarimeters like the Wide-Area Linear Optical Polarimeters (WALOPs) have a field of view (FoV) of tens of arcminutes. For efficient and accurate…
VERITAS discovery of very high energy gamma-ray emission from S3 1227+25 and multiwavelength observations
Atreya Acharyya, Colin Adams, Avery Archer +68
We report the detection of very high energy gamma-ray emission from the blazar S3 1227+25 (VER J1230+253) with the Very Energetic Radiation Imaging Telescope Array System (VERITAS)…
Compact Symmetric Objects -- III Evolution of the High-Luminosity Branch and a Possible Connection with Tidal Disruption Events
A. C. S. Readhead, V. Ravi, R. D. Blandford +18
We use a sample of 54 Compact Symmetric Objects (CSOs) to confirm that there are two unrelated CSO classes: an edge-dimmed, low-luminosity class (CSO~1), and an edge-brightened, hi…
Compact Symmetric Objects -- II Confirmation of a Distinct Population of High-Luminosity Jetted Active Galaxies
S. Kiehlmann, A. C. S. Readhead, S. O'Neill +10
Compact Symmetric Objects (CSOs) are compact (<1 kpc), jetted Active Galactic Nuclei (AGN), whose jet axes are not aligned close to the line of sight, and whose observed emission i…
Compact Symmetric Objects -- I Towards a Comprehensive Bona Fide Catalog
S. Kiehlmann, M. L. Lister, A. C. S. Readhead +8
Compact Symmetric Objects (CSOs) are jetted Active Galactic Nuclei (AGN) with overall projected size <1 kpc. The classification was introduced to distinguish these objects from the…