Research output: Contribution to journal › Article › peer-review
Extreme photometric and polarimetric variability of blazar S4 0954+65 at its maximum optical and γ-ray brightness levels. / Raiteri, C M; Villata, M; Carnerero, M I; Savchenko, S S; Kurtanidze, S O; Vlasyuk, V V; Marchini, A; Matsumoto, K; Lorey, C; Joner, M D; Gazeas, K; Carosati, D; Mirzaqulov, D O; Acosta Pulido, J A; Agudo, I; Bachev, R; Benítez, E; Borman, G A; Calcidese, P; Chen, W P; Damljanovic, G; Ehgamberdiev, S A; Elsässer, D; Feige, M; Frasca, A; Gaur, H; Grishina, T S; Gupta, A C; Hiriart, D; Holland, M; Horst, B; Ibryamov, S; Ivanidze, R Z; Jensen, J; Jithesh, V; Jovanovic, M D; Kiehlmann, S; Kimeridze, G N; Kishore, S; Kopatskaya, E N; Kurtanidze, O M; Larionova, E G; Lin, H C; Mannheim, K; Marinelli, C; Moreira Reyes, J; Morozova, D A; Nikolashvili, M G; Reinhart, D; Romanov, F D; Semkov, E; Seufert, J; Shishkina, E V; Sigua, L A; Skalidis, R; Spiridonova, O I; Stojanovic, M; Strigachev, A; Troitskaya, Y V; Troitskiy, I S; Tsai, A; Vasilyev, A A; Vince, O; Vrontaki, K; Wani, K; Watts, D; Zhovtan, A V.
In: Monthly Notices of the Royal Astronomical Society, Vol. 526, No. 3, 09.10.2023, p. 4502-4513.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Extreme photometric and polarimetric variability of blazar S4 0954+65 at its maximum optical and γ-ray brightness levels
AU - Raiteri, C M
AU - Villata, M
AU - Carnerero, M I
AU - Savchenko, S S
AU - Kurtanidze, S O
AU - Vlasyuk, V V
AU - Marchini, A
AU - Matsumoto, K
AU - Lorey, C
AU - Joner, M D
AU - Gazeas, K
AU - Carosati, D
AU - Mirzaqulov, D O
AU - Acosta Pulido, J A
AU - Agudo, I
AU - Bachev, R
AU - Benítez, E
AU - Borman, G A
AU - Calcidese, P
AU - Chen, W P
AU - Damljanovic, G
AU - Ehgamberdiev, S A
AU - Elsässer, D
AU - Feige, M
AU - Frasca, A
AU - Gaur, H
AU - Grishina, T S
AU - Gupta, A C
AU - Hiriart, D
AU - Holland, M
AU - Horst, B
AU - Ibryamov, S
AU - Ivanidze, R Z
AU - Jensen, J
AU - Jithesh, V
AU - Jovanovic, M D
AU - Kiehlmann, S
AU - Kimeridze, G N
AU - Kishore, S
AU - Kopatskaya, E N
AU - Kurtanidze, O M
AU - Larionova, E G
AU - Lin, H C
AU - Mannheim, K
AU - Marinelli, C
AU - Moreira Reyes, J
AU - Morozova, D A
AU - Nikolashvili, M G
AU - Reinhart, D
AU - Romanov, F D
AU - Semkov, E
AU - Seufert, J
AU - Shishkina, E V
AU - Sigua, L A
AU - Skalidis, R
AU - Spiridonova, O I
AU - Stojanovic, M
AU - Strigachev, A
AU - Troitskaya, Y V
AU - Troitskiy, I S
AU - Tsai, A
AU - Vasilyev, A A
AU - Vince, O
AU - Vrontaki, K
AU - Wani, K
AU - Watts, D
AU - Zhovtan, A V
PY - 2023/10/9
Y1 - 2023/10/9
N2 - In 2022 the BL Lac object S4 0954+65 underwent a major variability phase, reaching its historical maximum brightness in the optical and γ-ray bands. We present optical photometric and polarimetric data acquired by the Whole Earth Blazar Telescope (WEBT) Collaboration from 2022 April 6 to July 6. Many episodes of unprecedented fast variability were detected, implying an upper limit to the size of the emitting region as low as \10^\-4\\ parsec. The WEBT data show rapid variability in both the degree and angle of polarization. We analyse different models to explain the polarization behaviour in the framework of a twisting jet model, which assumes that the long-term trend of the flux is produced by variations in the emitting region viewing angle. All the models can reproduce the average trend of the polarization degree, and can account for its general anticorrelation with the flux, but the dispersion of the data requires the presence of intrinsic mechanisms, such as turbulence, shocks, or magnetic reconnection. The WEBT optical data are compared to γ-ray data from the Fermi satellite. These are analysed with both fixed and adaptive binning procedures. We show that the strong correlation between optical and γ-ray data without measurable delay assumes different slopes in faint and high brightness states, and this is compatible with a scenario where in faint states we mainly see the imprint of the geometrical effects, while in bright states the synchrotron self-Compton process dominates.
AB - In 2022 the BL Lac object S4 0954+65 underwent a major variability phase, reaching its historical maximum brightness in the optical and γ-ray bands. We present optical photometric and polarimetric data acquired by the Whole Earth Blazar Telescope (WEBT) Collaboration from 2022 April 6 to July 6. Many episodes of unprecedented fast variability were detected, implying an upper limit to the size of the emitting region as low as \10^\-4\\ parsec. The WEBT data show rapid variability in both the degree and angle of polarization. We analyse different models to explain the polarization behaviour in the framework of a twisting jet model, which assumes that the long-term trend of the flux is produced by variations in the emitting region viewing angle. All the models can reproduce the average trend of the polarization degree, and can account for its general anticorrelation with the flux, but the dispersion of the data requires the presence of intrinsic mechanisms, such as turbulence, shocks, or magnetic reconnection. The WEBT optical data are compared to γ-ray data from the Fermi satellite. These are analysed with both fixed and adaptive binning procedures. We show that the strong correlation between optical and γ-ray data without measurable delay assumes different slopes in faint and high brightness states, and this is compatible with a scenario where in faint states we mainly see the imprint of the geometrical effects, while in bright states the synchrotron self-Compton process dominates.
KW - BL Lacertae objects: general
KW - BL Lacertae objects: individual: S4 0954+65
KW - galaxies: active
KW - galaxies: jets
UR - https://www.mendeley.com/catalogue/04182746-cc52-398e-b1e0-42bcbec8092e/
U2 - 10.1093/mnras/stad3064
DO - 10.1093/mnras/stad3064
M3 - Article
VL - 526
SP - 4502
EP - 4513
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 3
ER -
ID: 114361807