43 citations · 263 across the 39 of their papers we have counts for
40 papers
Multi-band optical photometric variability of the blazar OJ 287 from 2015 to 2025
Alok C. Gupta, Karan Dogra, Mark Kidger +101
We present the most densely sampled multi-band optical photometric observations of the peculiar BL Lacertae object OJ 287 from 2015 to 2025 with a focus on its optical activity on…
Isochrone Fitting of Galactic Globular Clusters -- VIII. Homogeneous estimates of parameters for 27 clusters
G. A. Gontcharov, O. S. Ryutina, C. J. Bonatto +2
We use the Stetson, HST, and Gaia DR3 data sets for 22 Galactic globular clusters to select their members and fit their CMDs with isochrones from DSED and BaSTI for Fe…
Tracking down the broadband polarimetric properties of PG 1553+113
Riccardo Middei, Svetlana G. Jorstad, Alan P. Marscher +78
We report on a nine-month monitoring campaign of the blazar PG 1553+113, relying on three observations carried out in 2025 with the Imaging X-ray Polarimetry Explorer (IXPE) and su…
Multiwavelength quasi-periodic variability of the blazar Ton 599
Yu. V. Sotnikova, T. V. Mufakharov, A. E. Volvach +34
During the last 40-50 years, the TeV blazar Ton 599 has systematically experienced major outbursts detected in a wide wavelength range from radio to -rays. In this work, we pres…
Isochrone Fitting of Galactic Globular Clusters -- VII. NGC1904 (M79), NGC4372, and revision of NGC288, NGC362, NGC5904 (M5), NGC6205 (M13), and NGC6218 (M12)
George A. Gontcharov, Sergey S. Savchenko, Olga S. Ryutina +8
We estimate key parameters for the Galactic globular clusters NGC1904 and NGC4372 and update the parameters for NGC288, NGC362, NGC5904, NGC6205, and NGC6218, which were analysed i…
POLAMI Multi-Wavelength Polarization Study of AGN Jets: A Millimeter-Optical Comparison
C. Casadio, D. Blinov, I. Agudo +20
Millimeter-band polarimetry offers a powerful probe of AGN jets, accessing regions less affected by opacity and Faraday rotation than at longer radio wavelengths. As part of the PO…
First detection of VHE gamma-ray signal from the FSRQ TON 0599
MAGIC Collaboration, K. Abe, S. Abe +245
TON\,0599 (z=0.7247) belongs to the few flat spectrum radio quasars (FSRQs) detected in the very high energy (VHE, \,GeV) gamma-ray band. Its redshift makes it currently o…
Multiband optical variability on diverse timescales of the blazar Ton 599 from 2011 to 2023
O. Vince, C. M. Raiteri, M. Villata +72
(Shortened)Context: We analyze the optical variability of the FSRQ Ton 599 using BVRI photometry from the WEBT collaboration (2011-2023), complemented by photometric and spectrosco…
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…
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…
IXPE Observations of the Blazar Mrk 501 in 2022: A Multiwavelength View
L. Lisalda, E. Gau, H. Krawczynski +157
The blazar Markarian 501 (Mrk 501) was observed on three occasions over a 4-month period between 2022 March and 2022 July with the Imaging X-ray Polarimetry Explorer (IXPE). In thi…
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 Studies in Different Blazar Types. Part I: Correlation between Optical Brightness and Polarization Degree
E. A. Shkodkina, S. S. Savchenko, D. A. Morozova +11
We present an analysis of the cross-correlation between optical brightness and polarization degree in different types of blazars. The aim is to identify objects with simultaneous a…
Galactic warps: from cosmic noon to the current epoch
Vladimir P. Reshetnikov, Ilia V. Chugunov, Alexander A. Marchuk +6
Approximately half of all disc galaxies exhibit appreciable warps in both their stellar and HI discs. The typical warp amplitude is small (a few degrees), and only becomes noticeab…
Examination of the functional form of the light and mass distribution in spiral arms
Ilia V. Chugunov, Alexander A. Marchuk, Sergey S. Savchenko
Spiral arms are a common feature of local galaxies, but the exact form of the distribution of mass and light in them is not well known. In this work, we aim to measure this distrib…
Accurate Decomposition of Galaxies with Spiral Arms: Dust Properties and Distribution
A. A. Marchuk, I. V. Chugunov, F. Galliano +8
We analyze three nearby spiral galaxies - NGC 1097, NGC 1566, and NGC 3627 - using images from the DustPedia database in seven infrared bands (3.6, 8, 24, 70, 100, 160, and 250 mic…
Multiband Optical Variability of the Blazar 3C 454.3 on Diverse Timescales
Karan Dogra, Alok C. Gupta, C. M. Raiteri +79
Due to its peculiar and highly variable nature, the blazar 3C 454.3 has been extensively monitored by the WEBT team. Here, we present for the first time these long-term optical flu…
Multi-wavelength picture of the misaligned BL Lac object 3C 371
J. Otero-Santos, C. M. Raiteri, A. Tramacere +52
The BL Lac object 3C 371 is one of the targets that are regularly monitored by the Whole Earth Blazar Telescope (WEBT) Collaboration to study blazar variability on both short and l…
IXPE Observation of the Low-Synchrotron Peaked Blazar S4 0954+65 During An Optical-X-ray Flare
Pouya M. Kouch, Ioannis Liodakis, Francesco Fenu +134
The X-ray polarization observations made possible with the Imaging X-ray Polarimetry Explorer (IXPE) offer new ways of probing high-energy emission processes in astrophysical jets…
A wiggling filamentary jet at the origin of the blazar multi-wavelength behaviour
C. M. Raiteri, M. Villata, M. I. Carnerero +96
Blazars are beamed active galactic nuclei known for their strong multi-wavelength variability on timescales from years down to minutes. We aim to investigate the suitability of the…
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…
The Method of Searching for Rotations of the Polarization Position Angle of Quasars
S. S. Savchenko, D. A. Morozova, S. G. Jorstad +11
Observations of quasars show that the polarization position angle of the emission coming from them varies greatly over time, including periods called rotations during which the ang…
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…